Vilifying private landlords is helpful in advocating for public housing and denouncing Rentier Capitalism. Rather than seeking to live off the wages of others, people are better served by earning a wage themselves.
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.
https://www.theguardian.com/world/2022/jun/23/vienna-reclaim...