I upvoted you - at least, I hope I did. HN's vote buttons have such poor UX that a) it's difficult to hit the right button b) it's impossible to know, after doing so, whether you even hit the right button!
I love that there are no images, not even Unicode emojis, no ads, no side bars, etc.
There are alternatives to a simple word change. For example, instead of hiding both arrows, it could just keep the one you pressed, but in grey.
But at this point I think the bad UX on Hacker News has to be an intentional joke.