Because renter protection laws were written when it was mostly shady landlords doing shady *expletive deleted*it.
I don't agree with them all, but having had a shady landlord back in the day I can understand why we don't just allow them to show up, kick bad renters out, and change the locks. You would get (and did have) the real estate version of Buy Here, Pay here car dealers or Title loans.
Unfortunately, that protection also leaves the door open for the abuses from the other side we are talking about here.
Ideally, there'd be some hearing *very* early in the eviction process where you can claim that this is NOT a landlord-tenant dispute, but a case of squatting, and if it's found that there never existed a legit rental agreement at that hearing, the civil case stops, it kicks back to criminal proceedings, and arrest warrants are issued. That would require some liability on stupid, but legit renters to make sure they have copies of leases to provide the courts, but nothing's perfect.
Government being what it is, I suspect you will see their answer is there needs to be more government, probably in the form of an state or county office of lease approvals, that is required to review and approve all leases, and you can't rent real estate without registering it with the .gov. There will, of course, be a small fee to cover administration expenses of the new office.