What if the opposite happens and "oh shit, all plastic in the world is getting eaten, it's worthless now!"

I’m afraid it will lead to a cessation of anti-pollution efforts

The bacteria release carbon during the decomposition process. So this isn't a "solution" in any meaningful respect. It's an instance of evolution at work, as a surplus resource becomes a food source for innovative organisms.

Also, we look at this as some kind of "clean-up". In reality, this is a threat to one of our most useful durable materials. It'll likely lead to the development of antiseptics to kill these bacteria colonies, as the last thing anyone with a hard plastic shell on their vehicle or appliance or equipment wants is a colony of plastic-eaters deteriorating it.

I dont really follow.

You think people are going to point to this as a reason not decarbon?

Im sure that idiots will, but those people were never going to make any meaningful effort to decarbon anyway.