It looks like they left because they were no longer getting engagement. Not because "it was the right decision".

I'm glad they made the decision and I get their rationale for staying on other fascist platforms. But let's not let go of the fact that they would have stayed on twitter if they still had engagement.

Doing the right thing would have been "we know our work is important and we are encouraging our large and active audience to leave twitter and follow us to mastodon. In fact we put together a great blog post on how to make this easy for you."

Instead this reads as a whiney post about how Musk is minimizing their exposure, which, fair. But still they are trying to make it mean something more than it actually is.