The website where the speech is published to. They don't try to define hate speech in absolute, just define what they don't want to be associated with. Yes it's a slippery slope, but it's just this website opinion.
That's hilarious. You basically said "People who don't have the right opinions should go to jail!". Maybe if your governments had attempted to explain why the far-right is wrong instead of suppressing them, they would have been less radical. You can't just sweep the thoughts and emotions of your people under the rug, even (especially) if they are unpalatable to you, and hell, to me as well.