I just want to feed my stray cat

I've been feeding group of stray cats that lives around my block for few years now and I'm very proud of it. It started with just two cats and now there are about dozens that I feed daily. Obviously, I will adapt all of them if I can but I already have 3 cats at home. Lately people have been very hostile whenever I leave the food out. I'm spending my own money to buy these food. I even clean up all the cans afterwards once I see it's empty. I don't understand why they would go out of the way to throw these food out and I can see my cats are getting thin. I called police on them couple of times but they wouldn't do anything. I even have it on video of them actively throwing out the food. Talk about all the food waste. Is there anything I can do to stop them? I just want to feed these poor stray cats