That is because they themselves have to live somewhere. If they have to rent, then what have we achieved?
Harassing these people is entirely regressive.
People doing something entirely normal, like buying a place and living in it, are not the root cause of any problem.
(OK, I've heard of the practice of sleeping under the desk at work and using the company kitchen and shower, while AirBnB'ing your apartment for $. Good luck with that if you have a family.)