The phrase "rent free" is hilarious. It's an attempt to imply people are literally stewing day in and out because some weirdo writes annoyingly. Nope, it's only annoying when I try to read it. And that's clearly true for everyone else annoyed by it.
"Rent free" has always seemed primarily aimed at anyone to the left of trump. So I take it always as a distraction from being insanely and deeply wrong about something.
"Oh I'm wrong? Well you're obsessed!!!"