Weber's seventh claim:
More recently, Jewish historian Walter Laqueur "denied established history" by acknowledging in his 1980 book, The Terrible Secret, that the human soap story has no basis in reality. 
Weber makes this sentence sound very dramatic, especially since he insists on mentioning that Laqueur is Jewish, so we should look and see just what Laqueur actually said: "It emerged after the war that the [soap] story was in fact untrue." 
This was a completely nonchalant sentence from Laqueur, which Weber tried to turn into a dramatic concession and "denial of established history." Laqueur was only saying what several others have said -- that many people believed the soap allegations during the War.
Weber's eighth claim:
Gitta Sereny, another Jewish historian, noted in her book Into That Darkness: "The universally accepted story that the corpses were used to make soap and fertilizer is finally refuted by the generally very reliable Ludwigsburg Central Authority for Investigation into Nazi Crimes." 
The first part of that quotation is pure overstatement on Sereny's part: it was never "universally accepted," and she should not have phrased it that way. But what is most important is that Weber neglects to include Sereny's next sentence in his quotation. She continued:
The Authority has found after considerable research that only one experiment was made, with a few corpses from a concentration camp. When it proved impractical the idea was apparently abandoned. 
Although Sereny does not provide a citation for her quotation from the Ludwigsburg Authority, she is clearly stating that the Authority found that there was an attempt to make soap from human remains, but that it was given up. Weber deliberately omitted the second half of Sereny's quotation because it did not fit his thesis.
Weber's ninth claim:
The "RIF" soap bar initials that supposedly stood for "Pure Jewish Fat" actually indicated nothing more sinister than "Reich Center for Industrial Fat Provisioning" ("Reichsstelle für Industrielle Fettversorgung"), a German agency responsible for wartime production and distribution of soap and washing products. RIF soap was a poor quality substitute that contained no fat at all, human or otherwise. 
Weber is correct that the RIF soap was not made from human remains. But is it any wonder that people believed it during 1942-45, especially when Germans were taunting inmates at Auschwitz that they would be turned into soap?
What is interesting, though, is that Mazur never mentions any initials on the soap that he claimed was made at the Danzig Anatomical Institute. On the photograph of the soap evidence from the IMT, introduced as USSR-393, no initials are present. This photograph is reproduced on page 201 of The Hoax of the Twentieth Century, by Arthur Butz. It is also available at Nizkor: an overview, and a closeup of the soap.
Thus, the RIF soap really has nothing to do with the Danzig Anatomical Institute. The rumors that Jewish corpses were being used to make soap began to surface in the West as early as August 1942. The Danzig soap evidence is all dated 1944: Mazur testified that Spanner gave him the soap "recipe" in February 1944 (IMT document USSR-197), the recipe from the Danzig Institute is dated February 15, 1944 (USSR-196), William Neely's testimony stated that the soap tank was installed in March or April 1944 (USSR-272), and so on.
Himmler himself was disturbed by the rumors that bodies of Jews were being used for soap and/or fertilizer, since the Nazis' extermination plans demanded strict secrecy. On November 30, 1942, after Rabbi Stephen Wise mentioned the soap rumors to the press in New York City on November 24, Himmler wrote to Heinrich Müller, head of the Gestapo:
In view of the large emigration movement of Jews, I do not wonder that such rumors come to circulate in the world.
We both know that there is present an increased mortality among the Jews put to work. You have to guarantee to me that the corpses of these deceased Jews are either burned or buried at each location, and that absolutely nothing else can happen with the corpses at any location.
Conduct an investigation immediately everywhere whether any kind of misuse [of corpses] has taken place of the sort as listed in point 1, probably strewn about in the world as a lie.
Upon the SS-oath I am to be notified of each misuse of this kind. 
It is clear, then, that the RIF soap allegations were merely a rumor, even though many people believed it at the time. But the RIF soap rumors have nothing to do with the allegations regarding Professor Spanner's possible experiments at the Danzig Anatomical Institute. What Himmler's letter does imply, though, is that if Spanner used Jewish corpses (which has never been claimed or documented), then Himmler should have known about it.
Weber's tenth claim:
Shortly after the war the public prosecutor's office of Flensburg, Germany, began legal proceedings against Dr. Rudolf Spanner for his alleged role in producing human soap at the Danzig Institute. But after an investigation the charge was quietly dropped. In a January 1968 letter, the office stated that its inquiry had determined that no soap from human corpses was made at the Danzig Institute during the war. 
Actually, Spanner was investigated twice by German authorities: in Hamburg (1947) and in Flensburg (1947-48). Both times he was not prosecuted. Does that mean that he was completely innocent, or that there was not enough evidence to proceed with a case? One would need to read the complete file on Spanner from the Flensburg Public Prosecutor's Office to understand fully the reasons for the cases being dropped.
Weber's eleventh claim:
He [Yehuda Bauer] had the chutzpah to blame the [soap] legend on the Nazis. 
Douglas Frost has already been quoted above from his Nuremberg testimony that Germans taunted Auschwitz inmates that they would be turned into soap. Because of testimony such as Frost's, Professor Bauer believes that the Nazis "used [soap threats] as a form of additional sadism, in words this time, on their Jewish victims." 
In reading Mark Weber's article, it is clear that he is deliberately overstating the belief in the soap allegations among what he calls "exterminationist" historians, so as to make his debunking of it seem that much more important and dramatic.
In truth, most historians do not believe that soap was mass produced from human remains (most of those who even mention the soap allegations at all in their writings are survivors who either actually saw the "RIF" soap, or who were taunted by the Germans that they would be made into soap). No matter what we know now, it was widely rumored during the Second World War that soap was being (and even Himmler heard the rumors), so we can forgive the victims of the Nazis for believing that their persecutors would do such a thing.
Konnilyn Feig, writing in Hitler's Death Camps, is one of the few historians who argue that the Nazis made human soap. In his article, Weber overstates support for the soap allegations and attempts to build up this straw man so he can dramatically tear it down, and thereby hopefully cast doubt on the Nuremberg proceedings and the entire Holocaust. Whatever doesn't fit into his thesis is either glossed over (the Frost statement), misstated (the Judgment of the IMT), or omitted (Sereny's full quotation).
Weber also fails to differentiate between the various soap allegations. He is correct in asserting that RIF soap was not made from human remains. He is correct in asserting that there were no "soap factories" which mass-produced soap from human remains.
But he fails to address or respond to the affidavits of Sigmund Mazur, William Neely, or the second British POW, John Witton. All three worked at the Danzig Anatomical Institute. Weber merely states that Rudolf Spanner was cleared in 1948. But does the fact that a German prosecutor immediately after the War failed to bring charges against a prominent German academic mean that professor was necessarily innocent?
Source: The Nizkor Project. Reprinted by permission from the author.