[Tourist Guy]

On the other hand, why is there a warning on my toothpaste not to ingest it??

[Right Wing Professor]

Fluorides are good for your teeth in very small amounts, but toxic in larger amounts. So they can put them in toothpaste, where they're absorbed into your teeth, figuring you'll spit them out. But if you ate, say, an entire tube of toothpaste, you'd probably get enough fluoride to do you some harm. And for every dumb thing that could possibly be done, there's at least one dummy who'll do it, and at least 500 lawyers who'll be prepared to sue on his behalf.