I suspect you are full of it. I've been to lots of McDonald's locations, and I've rarely seen homeless people inside. Keep in mind I've been everywhere from California to Maine, From Kentucky to Florida to Texas. Nearly every state except the PNW, and I've never seen homeless people sleeping in a McDonald's (McD's used to be my goto with the $1 value menu when traveling). Ordering food? sure. As someone who once worked in fast food, I also know for a fact that management would kick them out, and so would the few dozen police officers in a lot of areas that walk in to get breakfast/coffee.

...Unless you mean Canada of course, however, I bet a well traveled Canadian would say the same thing.

Also, stop vilifying the homeless.