I think you're mixing up "there are bad landlords" with "landlording is bad". I'm sure there were good slave owners as well but it doesn't mean slavery was good. In someways landlords are modern slave owners. They can treat you humanely but at the end of the day they're taking a slice of your money just so you could have a roof over your head.
Hypothetically, if tomorrow your government would say that whatever house/apartment you live in right now is legally yours to keep would you miss your landlord? I very much doubt it.
Isn't this the world right now? Even you rent your landlord owns the house you rent.
Part of the reason people can't afford a house is because of landlords. If housing would be more affordable more people could afford houses.
Not entirely, but where I live the state has built social housing for people who couldn't even afford to rent a house. The state owns the house, but they're not trying to extract profits from the people living there. The state is simply giving them a roof because otherwise those people would live on the street. I see nothing wrong with that.