You'll want to take a look at your site's theme on mobile devices. On my iPhone 6 on iOS 9 (Safari), the navigation bar is fixed at the top half of the pane and takes up over half the screen.
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.
iPhone 5s, iOS 9.1. sorry to all reading my tweet about the snark. But I just find it so sad that I have so much rendering power on desktop (JavaScript on/off, elinks web browser, my rss reader), but if some silly CSS thing borks the mobile page, there's nothing I can do.
I came here to include a picture of the kakoune.org problem, but since you already have one I'll include a (hilariously?) similar picture of your tweet.
On the subject of kak, I tried it a few months ago and thought it was really impressed by it but didn't stick with it long enough to decide if it would be better than vim for me.
