I do not agree that one can separate Holocaust denial from anti-Semitism. Anything that helps perpetuate the belief that Jews are somehow inferior or evil or conspiring leads directly to the possibility of yet another pogrom or Inquisition or Holocaust or whatever you want to call it. In fact, anything that tries to convince other people that any culturally, ethnically or racially defined group of people is inferior and so deserves second-hand or worse treatment should be penalized.
BTW it is not illegal to deny the Holocaust in Canada. It is illegal to incite racial or ethnic hatred. Most of the countries where it IS illegal are either countries where the Holocaust was carried out so they know their own history and regret it, or they are countries that have many other limits to free speech.
And one more time: Auschwitz was NOT the only camp where Jews (and many other people) were deliberately killed, starved, experimented on, and allowed to die of preventable disease. The 6 million figure includes those who died in the Polish ghettos, in French camps, packed in cattle cars, shot by the police, or murdered by ruffians disguised as Nazi party supporters.
And you may think what you want, but as soon as you try to persuade others, then you are perpetuating hate.