Nobody concerned about rent price fixing thinks that we don't also need to build more housing here. This is just another part of the problem. Are you defending the practice?
And yet action gets taken about the rent price fixing, but not about actually encouraging more building.
I think it simply doesn't matter. The only reason it could have any impact at all is in an incredibly constrained market. Unconstrain the market and they just won't be able to; it wouldn't work.
Also - I don't think it actually affects prices. It's just that they've gotten good at seeking price equilibrium.