As a relatively new Beehaw user (I deliberately waited for the reddit exodus to subside before applying), I understand the reasoning. The "default" open nature of ActivityPub creates moderation challenges for a "well tended garden" - much more so than a more controlled space. I also understand the software (lemmy) itself is somewhat problematical, both politically and from technical/maintenance perspective.
I wouldn't be against moving - and I'd follow. The Beehaw groups are active and contain lot of good quality discussions, I'd assume that wouldn't change outside fediverse.
I'd be still free to access the fediverse through other kbin/lemmy instances if I wanted to participate and I wouldn't close my Mastodon account just because Beehaw decided to move somewhere else, so I wouldn't personally lose very much - and I would stand to gain a "safe haven" - a more closed discussion forum I could always turn to when the noise of the outside world gets to be too much.
For the sake of everyone moderating Beehaw and our communities, I'd completely understand. Fediverse is a very rowdy bar and as volunteer bartenders, it must be somewhat tiresome for you.
In the long term I'd worry about building a too small echo chamber without the required diversity for Quality Discussions and I'd also worry about "hiding" - it would be harder for fellow disenfranchised cretins to find us - and perhaps we'd lose good members. I know the Beehaw strategy priority is not centered around growth, but nevertheless, some kind of strategy would have to be devised to monitoring the long term health and diversity of the community.