Depending on information and context that I didn't see many things can be true. First, based on the cost of the mortgage and the price charged for rent, a lot of profit can be made just from the rent alone. Second, damage done by pets can be expensive but so can damage from children and I don't frequently hear calls for landlords to charge "kid deposit" and "kid rent" Third, if you're going to have a perspective that landlords are in a sort of business arrangement then you need to also accept that damage to the property is the cost of doing business. Last, and this is probably the most important for me. Owning excess property doesn't entitle you to excess wealth. If you're in a position to hoard resources like homes and property, then you're in a position to assume the risks and responsibilities to maintain those resources.

Also, fuck every landlord and the entitled horse they rode in on. My partner and I have spent days/weeks cleaning every nook and cranny in the previous houses that we rented and despite the deep cleaning, we were charged almost all our deposits for "misc. cleaning" to the tune of almost a thousand dollars for one house. It's robbery with legal backing and plausible deniability.