Yeah, the manufacturing biproducts (PFOA, PFOS etc) can certainly interfere with biological processes and endure in the environment for a long time, but PTFE is relatively benign as a solid... until it gets really hot and decomposes into carbonyls.

It's effectively inert to anything except molten sodium, magnesium, or the like.

It will depolymerize at temperatures above 650-700C.

Neither of those conditions is likely to be found in your body.

You could have said the same thing about asbestos.