For multi-unit housing a cash-poor leveraged property owner sounds like a likely slumlord, so I'd be happy to discourage that situation. More, less-leveraged, property owners instead sounds good.
For owner-occupied, it sounds like someone who made a risky financial decision because of perverse incentives. Which also seems good to revisit.
Also in these cases cash-poor is not low-income. It's likely to be high-income+high-obligations the way you describe it. Hard to get all that leverage otherwise.
It's not just slumlords though.
Rental yields are so low in the UK compared to the cost of finance, tax and maintenance that being a landlord has become completely unprofitable, which means the rental sector is falling apart.
Pretty much no landlords in the south east of England are cashflow positive on a monthly basis, and if they are they are yielding less than government bonds