Would homeless people be better off sold into slavery, better to sleep in a barn than a tent right?

A little something called the Constitution would get in the way of that.  Also, people have a basic human right not to arbitrarily have their freedom taken from them without due process.  Remember, just because someone's misfortune makes you uncomfortable doesn't mean that their rights will magically disappear for your convenience.  😒

Have you SEEN homeless people?! Who would buy such slaves? 

Slavery is illegal, and I notice you have no concern about how people become homeless.  Why is that?