You are oversimplifying things here. One can be a bad actor while remaining perfectly legal.
Your friend has an upcoming surprise birthday party. You didn't enter in to an agreement not to tell them, so you do. Your friend group doesn't sue you in a court of law, they shun you.
It's totally OK to decide that you want your project to be MIT, and call out hostile forks operating in bad faith. You're not going to stop them, but the community can judge for themselves whether you've got a point and which fork they want to associate with.
It's OK to say: well if you made the project GPL, they couldn't do what they're doing legally.
It's not OK to say: well you didn't make your project GPL, so you don't get to complain.