About the only thing you can do is get a dog--that should do it. You could set up a sprinker system that is motion activated. Once on the porch, their motion could set off a sprinkler that would soak them.
That really would discourage them.
Strays are only stray because their previous owners had abandoned them therefore the cats no longer trust the human being and I can see why. Maybe this is your last chance to show these poor starving animals and the reason why they stopped at your door step(?)If there is one human being left on earth that cares,you maybe the no. I found several homeless cats and kittens;I chose to take them in and feed them(when I had very little myself) then have SPCA help with expenses to have them all fixed then find loving homes,it was so easy and very rewarding.
Only to look into the sweet innocent eyes of these poor hungry babies. They do every thing a human does except work and if they could work in order to survive they would,but they were never given that option,therefore in the governments eyes they are non-productive as well as considered useless,how sad is that?
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.