A lot of downvotes happen by accident, as on mobile it's easy to fat-finger the down arrow. No need to comment, typically people will notice the mistake and correct it with upvotes.
If the mods read this, I'd like to put in a suggestion to, on mobile, add CSS that places the down arrow on the right side of the screen, nowhere near the up arrow on the left, and make the icons bigger so you can tap them without having to zoom in. Or if that looks cluttered, make the icons as big as they normally are, but make the clickable space larger using padding rules. This is the biggest UX problem HN has, in my opinion.
