I don't think beehaw doesn't fit the fediverse, I do believe it doesn't fit every user.
As I understand it, they want to be a safe place for a very specific audience, that is, people afraid to be harassed for who they are, that could also include people with extreme social anxiety, that's why it's so heavily policed and they defederate from a lot of other instances.
It's like having a heavily moderated subreddit, you wouldn't say it doesn't fit reddit just because they don't accept contribution from everyone.
The purpose of the fediverse is to have things spread out so one or few nodes dying doesn't affect the entire system, it's also about avoiding corporate control, the same principles on which the internet was founded.
I don't think it means having to trust everyone or accepting everyone into your local group.