Unfortunately slumlords are just so widespread. I rented 7 properties in the private sector 2012-2022 as a student and young professional, and to summarise
Home 1 - slumlord, the electricity main switch had rusted through (the man from the electricity board was ashen faced when he told us he couldn't touch it and to get an electrician in immediately), the cellar flooded with raw sewage, and the kitchen floor partially collapsed etc etc etc.
Home 2 - alright for a student property
Home 3 - very tatty and the landlords did naff all but not a full on slum
Home 4 - live in landlords who decided to evict me when I told them I'd just had much needed surgery scheduled and would be off work sick for a fortnight - they didn't want someone in the house all day! One month's notice issued, timed to expire when I was going to be in hospital.
Home 5 - actually really good landlord, I was sad to have to leave when my relationship broke down and I couldn't afford the rent alone (London 1 bed flat)
House 6 - landlord refused to protect the deposit ("oh it's just your last month's rent paid upfront"). He used to disappear for weeks at a time, completely uncontactable even in the event of an emergency. When a new job opportunity came up across the country and I needed to find a replacement for my room, he said that was fine, didn't issue any list of requirements, and then disappeared for several weeks. When he finally showed up again he said he didn't like the replacement tenant I'd found and had been trying to get in touch with him about for weeks, refused to issue a reference to my new landlord, and became very unpleasant about it all. He nearly scuppered an entire career move.
Home 7 - landlords painted over the damp before marketing it, I moved in in the autumn and before I knew it mould was springing forth from the walls and the landlord declined to do anything about it. Some of my belongings were ruined. I went into the cellar and discovered it was so damp down there that a very structural rolled steel joist was rusting. Not condensation in case you're wondering - it was both rising and penetrating damp. Somewhere along the way I'd inherited a dog (landlord permitted, the one good thing I can say about this landlord) so moving on became very difficult. Tried to take my parking space off me mid tenancy without compensation and evicted when I objected.
That's a potted history of my experience with private landlords - and these were the best options I found each time I househunted, in all cases as a fairly desirable tenant. I'm sure all of them were telling friends, family and MN that they were good landlords. Throughout that I was a student or young professional, often cited as the sort of person on this thread who 'should' be renting. I became very clued up on things like the Housing Act and often helped friends with their own slumlords. I was always fairly handy in terms of DIY thanks to my parents and knew how to spot damp, but even I had the wool pulled over my eyes.
In my experience slumlords are so very adept at covering up what they are until after you've signed on the dotted line. They outnumber the actually good landlords, and then there's the merely mediocre landlords in the middle.
If all landlords were like the one I had in Home 5, far fewer tenants would be calling for reform.
Don't direct your anger at policy makers, or tenants who want reform. Direct your anger at the slumlords who make reform necessary in the first place.