Cats are cats... they adopted you as the school bus window licking cat and feel sorry for you since you do not kill these pests yourself. In their little cat minds they are your protectors. As I said, cats are cats... there is a reason the Egyptians honored them. Dogs naturally form a pack but cats choose their pack.
One of the strays moved on me like Mae West, he just suddenly decided he was my pet and that was it, the other more feral stray I chased off for 2 years and she acted feral, but then one day she moved on me like a house cat, suddenly leg rubbing, meowing, even ‘pet me’, so what the heck, more cheap dry food.
I really do like them as a snake deterrent on my potting porch/front door area and it pleases me no end when they will look up from their food bowl and leap down to go kill something that I know I probably want killed.