So while I generally agree with your sentiment, there are some obvious ways that sometime could be an ethical landlord.

What if you have a house that's too big, so you convert a floor into an apartment? You're adding to the number of housing units available. Should you be forced to sell a portion of your house/building to whoever wants to live there? Or should you be able to rent it out to someone at a reasonable rate? Do we want rules that discourage people from potentially adding units to the market?

I feel like the "all landlords are evil" narrative is way too simplistic, and that simplistic view turns off people who would otherwise support reasonable limits on landlords and housing ownership. Like, it's obvious that we need limits and taxes on people who own multiple properties, and it's obvious that there are companies that exploit renters and drive up prices, but it's all more complicated than just "landlords evil lol".

Your assuming everyone wants to own property over renting.

House and property ownership has a lot of responsibility and expenses involved. Your water heater breaks well there is $1000+ your roof needs replacing there is 30K. All of that goes away when you rent as it isn't your responsibility.

If you own property it can be harder and more risky to relocate. I know a few people that bought in 2007 and then were stuck as they couldn't afford to move because they were upsidedown on their house.

Not saying renting is all sunshine and roses. I personally would rather own then rent but home ownership isn't for everyone.

But I do think it is a major problem when you have a few companies buying up all property so no one else can afford it. But I don't think being a Landlord is inherently evil.

Like in a housing shortage you’re hoarding property and profiting off it.

Housing shortages are caused by bad government policy: namely, low-density zoning. Direct your anger towards the entity that deserves it, and make them fix their fuck-up.

(Note: I'm not making some kind of Libertarian "all government is bad" argument here. I'm saying that in this specific case, the laws need to be changed.)

Not everyone is able or willing to own their property, what would they do if landlords didn't exist?

What's the alternative here? Only letting big companies without any ethical regards rent housing?

Sure, there's a good argument to be made that housing is essential to survive and as such should be provided by the government, but that's not the world we live in. In this society, it's likely someone is going to have to rent it out and I'd rather it be a person who actually gives a shit and can be held responsible rather than some faceless corporation.

I think everyone in your replies is conflating being a full time landlord and a part time landlord. One of them is definitely more evil than the other.

The vast majority of landlords are normal people renting out a portion of the home they live in as well.

What you are asking is that they should close those doors or have the rental be free? Either of those situations is bunk.