To a trapper, an "anti" might just be anyone who wants any kind of government regulation of trapping.
A more reasonable definition of an "anti" would be someone who wants to ban recreational and commercial trapping, but allow professional, publicly-accountable wildlife management and pest control.
An animal-rights activist "anti" might want to ban all lethal trapping. Problem animals that would be caught alive in cage traps might still be killed, but in a targeted and more humane way.
Here's a test: view the Predator Defense videos on YouTube and think about what kind of an "anti" you might be.
Also check out the news of Dogs Killed in Traps.
To be fair, you'll need to learn something about the realities of wildlife management. Sorry, no simple links for that huge topic.
Maybe you're not an "anti" at all. Maybe there's another way to deal with the irresponsible, unethical trappers who inflict this kind of damage on wildlife and domestic animals. Maybe their trappers' associations can keep them in line and make responsible, ethical trappers out of them.
However, the balance probably lies somewhere between the extremes of "anti" and careless trapper.