The essence of capitalism is that capital can be used to produce income. Rent, and specifically residential property rent are a tiny fraction of that.

Why it's possible to highlight the negative effects of capitalism in general, I feel like that's a "boil the ocean" problem.

The root of the housing issue is supply. It doesn't matter who owns the accommodation - there's a shortage of it - and that's driving prices up.

I more useful strategy IMO is to look at policies that would encourage all levels (private and govt) to develop more housing and increase the supply.