Beehaw is hardly and echo chamber. Generally defederation is done because of significant trolling or other negative behavior from an instance, not a disagreement with a philosophy.
I think an excellent example of how Beehaw allows opposing opinions is that you and I, who clearly disagree, are still able to talk about it.
The thing we want at Beehaw is respectful discourse. So long as neither party is insulting the other and conversation is productive it doesn't matter if the opinions differ.
That said, I myself would probably not follow Beehaw off of ActivityPub. I prefer the content on Beehaw to most of the content in the fediverse, but I don't want to maintain multiple accounts and Beehaw would definitely have less content if it moved off of the fediverse.