I thought that already happened with the HCA or whatever it's called now?

Many landlords do not like letting to council tenants though. They are statistically much more likely to damage and less likely to maintain the property. The difference between good and bad tenants makes an enormous difference to the cost of letting both financially and in terms of stress. My parents have a tenant who complained that the kitchen was dirty and needed cleaning. It was clean when they moved in ffs. They've also managed to break the radiators and god knows what else...

I haven't looked for rental property in a long time but when I did a common requirement was no DSS, pets or smokers.

Or Irish or Blacks. Actually I guess you weren't in 1950s America so maybe not

The "no pets" thing can actually be a huge barrier for renters. Two of the girls at work have dogs which they have found restrictive. Our own Zippy has a snake and over 9000 fish, frogs and snails. She also wants to keep birds of prey, and is currently looking for a new house to rent. I can imagine quite a few potential landlords raising an eyebrow at that menagerie