My comments from the perspective of a landlord weren't intended to generalise pet owners.
I own two cats (although I suspect they actually own me) and have previously rented houses and have offered a per-cat additional deposit in cases where landlords were adamant.
One of my cats is easily stressed out which can lead to uninary tract infections and which may have contributed to her chronic irritable bowel syndrome.
Both conditions (the former intermittent, the latter constant) can result in unexpected indoor urination and surprise vomiting.
Cleaning up either is perfectly achievable given the correct care and attention.
Despite being exposed over many years to a variety of cat by-products, I still haven't grown accustomed to the smell of cat urine such that I could ignore it. Sometimes I wish I could!