That's a lot of confidence for a field of research that is relatively new

It's "research" that's highly politicised and much of it is junk (see the "black plastic" scare not long ago).

Synthetic fibers are around a century old by now, other plastics applications more than that, and everyone has already been exposed to microplastics. If they were as harmful as the scaremongers want us to believe, we would've noticed long ago.

Just like non-ionising radiation from radio, this whole plastics scare is another nothingburger.