@amszmidt You can use a different term if you want, it doesn't change the fact that if you use GPL code, your code base *has to* become GPL as well. That's the virality I'm talking about. You can't use GPL code in your MIT licensed project, so the third-party code "injects" the requirement of GPL into your own code base.
If constructed right, I'm sure there's a scenario where the plugin would need to be GPL licensed and there's a scenario where it doesn't need to be. That makes it uncertain.