I don't think you'll find any vets that say it's okay to use. People say lots of things, like some say it's okay to inject undiluted Tylan 200 into the sinus cavity of a bird. that's an extreme example, but there is no way I will endorse something I think could be dangerous.
But anything can be dangerous, not just garlic. I gave it to Flapper along with ACV and coconut oil for a week, and he's fine. And vets would lose money if they told the patients to use these things. They do what they were trained to do. My veterinarian is honest, and allows us to do things that most other vets don't. She's the only vet, and it's a smaller place, so that makes all the difference. I'll talk to her sometime.
My dog/cat vet isn't interested in making money. Of course he charges an exam fee, but he doesn't insist that I buy medications from him, he's quite willing to write prescriptions that can be filled at a pharmacy. Same with my avian vet, she charges $68 to examine 4 birds, spends at least an hour with me, and sends me on my way with prescriptions that I can get filled for less at a pharmacy. Of course I'm more than willing to buy the drugs from them if they need to start treatment right way. Did you know that most vets don't make that much on the drugs they sell?
All chemical wormers that I know about *are* available *without* a prescription, so where is this money making op?
Ask your vet if she thinks you should suggest that other people feed garlic to their animals. Ask her if it's okay to feed it to your animals...