Keyplus90 -
I agree with you in one respect – the imprisonment of a person because of their belief(s) is obscene. If some believes that the Holocaust didn't happen, then that's their choice. I don't agree with such people, but I don't think they should go to prison for being a misinformed, deluded idiot.
Interesting that you state, “... If I deny holocaust or even if I do not agree with the scale of it then I can be arrested in few countries. So what happened to my freedom of speech?”.
I find that really interesting because Islam has a deserved reputation throughout the world for apparently wanting to suppress free speech. In many Islamic countries you do not have the democratic right to protest and you certainly don't have free speech.
You also stated earlier, “... as I believe freedom of speech should not be used as freedom to insult”.
Keyplus, just so you understand – free speech means:
The right to openly criticise another person's actions without fear of retribution;
The right to openly criticise another person's beliefs without fear of retribution;
The right to say what you think – no matter how ludicrous, without fear of retribution.