Who are we protecting? Landlords or tenants?
It's not the job of the government to protect either. The market does that.
Two people entering into a strictly voluntary agreement that exchanges use of property for money isn't the concern of government.
If either side violates, or is believed to have violated, that agreement, it's up to the courts to decide if redress is required. That should the extend of the state's involvement.
So landlords should be free to discriminate against any tenant for no good reason? Landlords should be free to collide on rents, lease conditions and residency requirements with no in put from representative governments. No health and safety regulations are needed because the landlords who are actually slumlords should have a free hand. What about rent subsidy vouchers? Should the voucher issuing authority not inspect subsidized units?
To be fair, rentors discriminate all the time based on credit / rental history / pets / children / job status / marital status, etc. However, if you're speaking about racial or religious discrimination, then the civil courts can decide that matter and it's covered by tort law.
Collusion (collision?) also occurs, rental prices generally follow the market for similar locations. If the market will bear a certain price, a rentor would be a fool not to charge the highest price the market will sustain. No collusion or cabal of rentors can force prices above what the market will bear for a certain location and only a government can hold prices artificially below a market -- which usually leads to the detriment of the housing market.
No one rents a place sight unseen. If a rentee believes a property to be unsafe or unsanitary, why did they enter into the rental agreement in the first place? Unless they have been assigned housing by the state, no one lives in a slum involuntarily. If a place become unsanitary after an agreement has been signed and it's not the fault of the rentee, a court can decide the redress.
You might have guessed, I'm against any form of taxpayer funded rental subsidy. Someone else's inability to buy weed
and pay rent isn't my responsibility as a taxpayer.
However, if a rentor is willing to accept taxpayer money for the rent then they have already entered into an agreement with the state (in effect, the state is a rentee of the property just the same as the actual tenant) and has agree to give the state the same access rights as the tenant.