@markush Many European countries did not support such an international document, because it is absolutely natural that Nazism and similar concepts are purely subjective concepts. That is, who is considered a Nazi, who is called a fascist, as a rule, depends on the point of view of the speaker.
And why, in this case, the point of view of one expert should prevail under the law over the point of view of another and be enshrined in international law?
Also, introducing into international law any ban on the active discussion of such ideas will in fact be a ban on historical research in this area.
It's like passing a law to ban LGBT people. I can say that you are gay and they will put you in jail. Similarly, I could say that you are a Nazi. Purely technically, such documents add a lot of problems.