I agree that sometimes a landlord might be subletting something and therefore they might not own it, but what you write is mostly ridiculous: if a landlord owns the property, they are the property owner.
I think you missed the point. In math terms: landlords are a proper subset of property owners, not equivalent. Using the latter term instead of the former is likely to change the meaning of the sentence.
For example: "landlords should pay more taxes" is very different from "property owners should pay more taxes".
Your explanation doesn’t square with the weird comment about landlords wanting to be conflated with property owners, which I read as meaning that the parent thought they weren’t subsets.
Apologies if I was unclear. I meant 'conflate' as in 'treat as equivalent'.
As for landlords perhaps wanting to be treated as equivalent to property owners, I think the previous poster gave a suitable example of why this might be the case. In many places landlords are being targeted politically (rightly or wrongly). It would be to their political advantage if all reference to them was conflated with regular owner occupiers by use of the term 'property owners'.
