Is it wrong to set out food?

It is very hard not to feed those adorable wild things. However if you do it all the time they become dependant on your generousity and lose their natural ability to hunt their own food. I used to feed the raccoons that came to my deck in Colorado and then the foxes by our back fence so I know how much you want to do it. The best thing you can do is to trap the kitties in a live animal trap baited with the food, then take them to a vet and have them spayed/neutered and then release them back into the wild. They will still come to you for food so that problem won't be solved but at least they will not constantly reproduce and create a larger problem to deal with. We used to have a lot of feral cats in the outside patio where I worked in California and finally the maintenance guys did this for them. It worked out well and some of the cats even accepted humans and were successfully domesticated. The others still hung around for handouts but quit producing more and more so we were not overrun with cats. Good luck with whatever you decide.