I understand your feelings completely. I don't know if you remember the 2 dogs I found this last fall. I searched all day for the owners & just as luck would have it, a friend of mine dropped by & her daughter knew the owner. They both belonged to the same family.
Well, they have been coming to our fence now for some time. I, like you, try to ignore them. I've been to their house a few times, to let them know they were out, but it just keeps happening time & time again & there's not a darn thing I can do about it.
People infurate me If you can't take care of your dog(s), don't have them.