Beehaw "moderators" don't have an issue with their user base checking out other communities. As is clearly obvious from the fact that they aren't defederated from all other instances.
They do have an issue with droves of unvetted users from other instances trolling and harassing their community though. And the most effective way to deal with that currently is to defederate from the instances that the majority of those bad-faith users are coming from. The unfortunate (and unintentional) side effect is that Beehaw users won't be able to interact with any of the users from those instances.
This is a situation born out of a combination of
- lack of manpower and moderation tools
- gaps in the configuration of inter-instance interactions
- the way the internet works
You can disagree with this decision and users are free to switch, but this meme is a poor caricature of the actual effects of Beehaw's actions and (at least in my estimation) of their intentions.
The decision to defederate is less of an attack or an indictment against the other instances and more of a practical necessity for them to protect their community.
If the user base of the lemmy verse keeps growing I wouldn't be surprised if either
- more granular control over the way instances interact with each other is implemented and the restrictions are softened or
- the amount of spammers and trolls reaches a level that forces more instances to vet their users and the defederation is lifted entirely or
- more powerful moderation tools show up and in combination with a greater number of people moderating makes the pre-screening of users unnecessary
