I think it sounds somewhat reasonable that they defederated hexbear. Whether left or right, too much politics outside of politics communities can ruin the fun for others. I would personally defederate them too.

Defederating lemmy.world would mean defederating one of the biggest instances, which would make you lose a lot of big communities. Other instances might see that you defederated lemmy.world for what they might find a dumb reason and defederate you for being unreasonable. This would be bad for everyone involved with your instance because they’d lose out on all the discussion around whatever topic. This would also be bad for people on lemmy.world who might’ve wanted to take part in discussions on your instance. If you as an instance defederate lemmy.world, it could be bad for everyone.

Of course, if you host an instance just for yourself, you can do whatever you want.