That kind of polarization does not just happen for no reason; people reach that frustration after repeatedly seeing themselves and others being downvoted anyway, no matter how flowery and sugared their dissent is.
Downvoters don't care how polite someone is, if they're saying something they don't want to be seen. It's a zero cost action for them, and easily lets them control what opinions other readers see about a topic.
Example: In every thread about browsers, if most people say they dislike Edge, anyone simply saying "Hey I like Edge, it's not so bad" gets downvoted.
So after a while that Edge user will be preemptively defensive the next time they voice their opinion, if they even feel like participating anymore.
HN is a place I spend a lot of time because the culture here is reasonable.
To me, saying "Hey I like Edge, it's not so bad" is pointless shit-stirring. It's looking to start trouble for no real reason.
It's a low value comment. The guidelines actively discourage that, so it's not surprising that it would be downvoted, having nothing to do with "disagreeing" per se.
If you have something meaty and thoughtful to say that disagrees with the majority view, the HN crowd will give you a fair shake. Jumping into the midst of a discussion where everyone is saying "This is junk!" to say "Well, I like it!" isn't thoughtful or meaty.