It's been obvious for a very long time that up-/downvoting is just a horribly broken mechanism. Much more so, if it's upvoting only. Twitter tries to ameliorate that with the ability to block people, but that's just a crutch.

The solution is laughably simple in theory, but it seems to keep getting ignored: Don't use a simple sum of votes. Instead use some method - any method really - to weight the votes of users depending how much their past voting behaviour correlates with your own.

I've been writing about this over six years ago, for example here: https://news.ycombinator.com/item?id=2095500