I had occasional rats and roaches in my previous apartment and every time I killed them I’d feel like I was a selfish, ego centered bastard. I’m glad in my new apartment I don’t have those issues, but sometimes I still feel guilty of killing them.
It depends on the animal.
I will happily kill houseflies. And use rat poison on the rare occasions rats get into the attic to prevent damage to the wiring up there - hopefully i have found where they were getting in over winter and now have a cat. Quite happy for them to live in the garden.
Spiders are fine wherever.
And I don't feel guilty using slug pellets on the vegetable plot - but I do use companion planting to attract the damaging bugs away from the veg.
I avoid killing all animals, period.
Besides I used to keep hooded rats as pets, but wild rats in the ceiling can chew wires and start fires, so in Haiti we'd collect baby boa snakes from a nest in the radio station ceiling and put one in each mission home attic to scare away rats.
I don't consider killing destructive, invasive animals as morally wrong, even though their presence here is the fault of the humans who brought them here.
When I was young, Yes. I am not so concerned of late. While I would wish to to so with a minimum of suffering. Ultimately, I am unconcerned. Any species that perceived us as a danger or even an inconvenience would not likely hesitate or share our concerns.
I dislike the NECESSITY of killing or hurting another creature, however we know we cannot manage to live without harming other beings.
Even if we only eat fruits, we harm bacteria and other things. So, relax, live as gently as you're able, and love yourself too.
I'm fair but I don't feel guilty. All life has a right to life but there are exceptions. Once a field mouse got in my house and I trapped him in one of these live traps where you can release the animal back out into the wild again. I took him out into the yard and let him go. He ran like crazy back to the house. I trapped him the second time and this time I drowned the little bastard.