Why are Landlords Hostile to Pets?

Many landlords are hostile to pets.  My experience is that students are worse than pets.

"Brisbane vet Michael O'Donoghue has seen too many people have to give up, or put down, their pets because they could not find a rental property that welcomed animals.

"It's very heart-breaking, people euthanising their beloved pet because they can't find accommodation," he said."

See SMH