If they'd instead chose to fork the plugins themselves (the only parts where the licenses changed, all except two are Apache V2) then all users can pick and choose which ones they include in their projects, and it doesn't fragment the ecosystem at all. Your plugins would compile in my project, and mine would compile in yours.
The part they're choosing to fork here, which will cause this rift in the community, is still MIT licensed: https://github.com/redpanda-data/benthos. If they simply chose to continue using this MIT part we can all live happily together in a utopian society fully saturated with plugged blobbery.
Edit: I'm bit a baby brained so I forgot that I'm literally streaming live in 30 minutes in order to explain all the changes in detail for those out of the loop: https://www.youtube.com/watch?v=X8nVdUuWZ80