Oh this is normal. People upvote the title, then comment, then read it if the comments aren’t agreeing with their preconception. Humans are a mess of a species.
There isn't a website on the planet that allows for votes where it doesn't very often happen that they provide a viewport into the boundless stupidity of the human species.
I wonder how H.N. and similar websites would work if ranking was purely a function of activity and not of votes — simply push to the top whichever branch of the tree has the last reply so highly debated news is statistically more often at the top, but whichever link had the last reply somewhere will be currently at the top.