These are private sites, so, in reality, you have no rights at all... People have a license to discuss in their private blogs any subject they wish. It is then up to the reader to choose whether they wish to read or to move on.
'Here', as far as I'm concerned, is not America. I haven't a clue what your First Amendment is, nor do I wish to know. Typical American arrogance
Actually, any viewpoint that is espoused will insult somebody. So, you really can't ever claim that you weren't insulting.
I am sure that the way you have referred to Kupe (who is Jewish) is probably insulting, especially since this is his post, not yours. You essentially walked into his living room, invited yourself into his conversation, then told him that he should cease his discussion because you were offended by it.
Why are your "rights" more important than his?
Hmm... you seemed to have proved his "American arrogance" point. Do Americans know the doctrines of the laws of the UK? No...not typically, and I doubt many people care. So, why should they care about the laws of the US, especially if those laws don't pertain to what they are involved in?