I agree that plastics probably do have more positives than negatives, but my point is that many of our innovations do have large negative effects, and if we take them into use before we understand those negative effects it can be impossible to fix the problems later. Now that we're starting to understand the extent of plastic pollution in our environment, if some future study reveals that it's a causal factor in some of our diseases it'll be too late to do anything about it. The plastic is in the environment and we can't get it out with regulation anymore.

Why take such risks when we could take our time doing more studies and thinking about all the possible scenarios? If we did, we might use plastics where they save lives and not use them in single-use containers and fabrics. We'd get most of the benefit without any of the harm.