Why do they allow an algorithm to do it?
That’s all there is. Doesn’t mean it’s great, doesn’t mean it’s always wrong, either.
And I’m far from defender of how Quora mods do things, but I concede: the mod bots are often stupid, but they are not useless.
Why do they allow a broken algorithm to do it?
Because we’re not in 2030 yet. And these kinds of bot decisions actually need more smarts than a bot can currently muster.