Are you saying there should only be owning housing?

Isn't this the world right now? Even you rent your landlord owns the house you rent.

What do the people that can't afford a house or flat do?

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.

Is it entirely the states job to build housing then and give housing away?

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.

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.

There are a lot of videos that made me question the validity of his "science". While I didn't want to spend time dissecting a specific video but with the videos piling up I decided it would be easier to just not watch him. I don't watch videos to question whether it's bullshit or not, so I ended up watching videos where I don't have to ask that question.