Any that were slums could have been dealt with. No new ones permitted. It did not have to involve banning them outright without a solid durable basis for meeting the accomodation needs of their occupants.So did slums. So do homeless hostels and hotels serving as emergency accommodation. As in fairness do massive mansions in leafy suburbs occupied by MCDowell and his ilk. Same way drug dealers fill a role in the justice system.
Comparing them to drug dealers? Absolute nonsense I doubt that even made sense in your own head because it makes none on the page.