I'm going to remove a feral cat community
Why do you want to remove a feral cat community?
I noticed several feral cats are causing some sort of infection.
I think it would be better to try and warm up to them, take care of them for a bit, and then try to get to them to a shelter for adoption. Harming them would do no good, as they never asked to be in such a situation.
What gives you the right to say what I'm doing wrong? Do you know how hard it would be to compost the bodies of these feral cats?
You have no right to kill these cats. You should contact animal control and let them decide what to do with these cats.