It’s not like shaving a husky. For some cats, cutting their hair is fine. It’s not recommended for all cats, but there’s nothing inherently wrong with it. Most cat breeds don’t have an undercoat like huskies that gets messed up when you shave them. I actually don’t know of one that does.

If it were just for aesthetic purposes, yeah it’d not be good. But if a vet said it’s fine, chances are they made sure the cat’s situation and health and behavior were appropriate for a haircut.

There are other ways to control hairballs, but it doesn’t seem like they’re doing anything too drastic for the wrong reasons.