HN doesn't really allow downvotes though. At least not unless you've reached a m...

roryokane · on April 1, 2021

I became able to downvote after reaching 500 karma. The minimum requirement might have changed to 1000 since then, I forget.

Even after reaching that karma amount, you are only able to downvote comments within a day of their posting. After a day, only upvotes are possible.

luckylion · on April 1, 2021

It does. I don't know what the threshold is, but it's not too high. I believe it's 500, but I might be wrong.