nirvana has some opinions around Apple which are seen by some as pure trolling. (Not saying they actually are trolling or should be downvoted or anything else.)

nirvana mentions global warming. While it'd be nice if HN could have calm discussions about science it's obvious that HN cannot have calm discussions about a variety of hot-button topics. This is even mentioned in the guidelines which urge against topics which are shallowly but intensely interesting. These are topics where people have already decided their position and they're not going to go into the discussion with an open mind. They're also topics where people tend to want to teach others the "Truth" that is being suppressed.

This unfortunate combination means that nirvana gets heavily downvoted on some comments.

It is a shame - dissenting opinions (if correctly formed) can be very useful.