A friend of mine had 4 houses she rented out, she's now has two apartments in Lytham. The reason being non payment, causing damage to the properties and stealing a boiler, it was too stressful. Some of her renters were on benefit's, they were the worse because they got their PIP/Universal Credit payments which included rent allowance but "forgot" to pay their rent.
Before anyone pulls me up I know I've used a tautology.
It's not discrimination it's purely financial, she was in danger of going broke, most Landlords have finance to pay on properties with hopefully a profit at the end of the year. If some renters are likely to default it's a business decision not to take them on.