Because "free trade" does not exist unless all regulations go away. But American mega corps (which includes political parties) like to pretend free trade means

Because "free trade" does not exist unless all regulations go away. But American mega corps (which includes political parties) like to pretend free trade means just get rid of the regulations we don't like, but keep all the ones that prevent competition. Rent control is not even close to the only barrier to the free trade of housing. It's one of the most minor, but its one of the few that actually protects consumers verses protecting the interests of mega corps like most regulations do. So of course the mega corps are opposed to it.