

The kind of people you’re talking about are not going to be affected by Blahj defederating feddit.uk. If a person is looking to commit harassment then they’re going to make a new account and no amount of defederation will prevent this (unless Blahj, like Beehaw, goes private) because it is trivial to make an accounts on non-blocked instances.
They don’t need to moderate the entire fediverse, they only need to moderate their communities.
In this situation, what is the goal here? What purpose is served, from the point of view of a Blahj users if another user, who isn’t a Blahj user and isn’t commenting in Blahj communities is banned from a non-Blahj instance? Users can already block instances, communities and individuals on their own. Users can already choose to only see local Blahj communities if they want to ensure that they’re in a safe space and the Blahj admins have full control over the Blahj communities.
The Blahj admin’s opinion doesn’t matter when the topic is a non-blahj user, in a non-blahj community. They’re certainly free to block whoever they want, or not; and federate with who they want to or not.
But, in the context of “Are they power tripping or not”, choosing to defederate an instance simply because an admin brushed them off puts it squarely in the “power tripping” pile. It wasn’t that feddit.uk was suddenly the source of a lot of transphobic attacks, or that they allow bigotry… it was that feddit.uk has different moderation practices then Blahj and refused to change them. It’s petty and power tripping.
You’re running the ‘Are these people are power tripping?’ community in the Fediverse, a community of majority left wing people, and you get a lot of people posting about a single instance, so much so that it dominates the posts to the point that requires moderation intervention.
You can read that in a lot of ways.
One of the ways to read it is that the instance’s admins are power tripping. That doesn’t mean that they’re not trying to create a safe space or that there are not some transphobes. All of these things can be true at once. Some people get caught up in the righteousness of their cause and fail to consider how their actions affect others.