Okay even accepting that Zillow made big unforced errors, that doesn't sound believable. Like, they don't make the offer conditional on someone looking at it in person for red flags?
In my area, OpenDoor was buying sight unseen. All they required was a 10 minute zoom call where you walk them through the house. Zillow actually sent out someone to do a home inspection (although a bit more cursory than what a typical buyer would pay for). This may have varied by market though.
Walking through a house with a high quality N95 mask in a hurry you might not notice the cat pee smell - or chalk it up to there being 13 cats and once they're gone the smell will go away.