They lay it out very clearly in their long-winded "philosophy of beehaw" post (which you must read prior to application): anyone being a jerk because of bigotry or because the people in charge don't like them or are having a bad day or feel like exercising their power or they are not sufficiently singing along.

This is the downside of federated sites like this. While one person can't take the whole thing down, there's lots of small groups that can do stuff like this. Beehaw has dome of the biggest communities, and a small group just shut them down for a lot of people. And you can't sign up to their community, without a completely opaque sign up process that barely works.