Modern houses with their insulated walls and double windows are better at withstanding summer than the ones I’ve lived in while my only solace for 85+ degree nights was a fan.
I’m all for demanding proper maintenance from landlords, even if it’s not on the lease. You visit a unit that has a thermostat on it, that’s advertising it has a working AC. It’s disingenuous from the landlord to claim the AC is decorative.
But claiming air conditioning is essential is utter horseshit.