However, many people's profiles are linked to their real selves, so this isn't a non taboo area for them.
At the other extreme, if you take ideas that are currently say 90% accepted, and you talk about them in such a way that the other 10% feel strongly pressured to change their minds, you can seriously offend them. You can generate resentment, by saying there is no reasonable middle ground, and the wrong view is wrong, and elaborating in detail on how bad it is, and why it's so bad, and how they are hurting their friends and family and themselves by not changing their mind, etc... Even if all that is true, and even if there do not exist any half-decent arguments for the 10%-and-declining view.
You can even offend people who agree with you, but who think you're putting it too strongly, or something. Even if they have no rational reasons for saying your claims are too strong. They may not even consider it a matter of truth, but instead a matter of being nice, or something. Most people think that way, some of the time.
What you are actually talking about matters too. On some subjects, it is easier to trigger defensiveness, on others, harder. So there are some "least possible to say" things, and they are a lot worse than discussing sexism.
PS I think you may have a typo with that double negative isn't + non.
He could be seriously offended, but then not hate you. He might realize you were right, and be glad to find out.
Or if he isn't offended, he might still recognize that many other people would be. He might also consider whether he would dare say it, and discover he wouldn't.
So those are two ways you could win. However, in both of those cases, while you'd win with yters, you'd lose with a majority of the audience. You could only win with a majority of the audience if you said something that can be safely said on Hacker News (and thus you were wrong).
- i will seriously offend you
- i won't seriously offend you
so either you'll hate me, or think i'm wrong. i don't see how i can win.