Original sentence: Because of this, Holocaust denial has been illegal in a number of European countries and Canada beginning shortly after World War II.They argue that since Holocaust deniers argue a preconceived theory, namely that the Holocaust did not take place or was a hoax, that they are not attempting to 'revise' history, but rather deny verified facts
Edited sentence: Because it is often motivated by an antisemitic or neo-Nazi agenda, Holocaust denial has been illegal in a number of European countries since shortly after World War II