Because every decision in life is about trade-offs. Sure you could completely stop using plastics in the microwave, but that means buying new items that are potentially more expensive and may have other disadvantages. And for some plastic items there may not even be a viable replacement - for example I'm not sure how you would replace flexible pouches.
So to make any sort of sensible decision you need to know how bad these plastic particles really are, to weigh that against the cost of avoiding them.
So to make any sort of sensible decision you need to know how bad these plastic particles really are, to weigh that against the cost of avoiding them.