(I'm not saying HN should do exactly the same thing, but one example is Slashdot's system where a comment can get downvoted in a way that tags it specifically as trolling/offtopic/whatever - https://slashdot.org/faq/mod-metamod.shtml seems to describe it alright)
It's a totally sane motivation it just doesn't obviously make a messageboard better.
I guess that's probably the best way to summarize this argument - the extraordinary burden demands extraordinary benefit and not even the people who are really into this idea often argue the benefit would be commensurate with the burden.