Fishing violates their freedom far more than me trying to protect the fish violates the freedom of fishers. But like most injustices, the oppressor sees their oppression being stopped as their rights being taken away.

Is "presence of mind" what gives somone moral relevance? If so, you'd have no problem with someone hunting infants or humans in comas, right?

The people who would be fish-blocked by me do not need to eat or harvest meat, so me trying to stop them is just as "militantly jainist" as trying to stop dog fights, another form of unnecessary violence to other animals.