It’s as ridiculous as that.
When you’re young, things that’ve happened just don’t seem to click. Even catastrophic things, like death. Maybe it does click for some kids, but most of them just process a sudden tragedy, they may ask questions, and they may express sadness, and then they move on.
The problem with plastic, if you haven’t already begun to notice in the past few decades, or since you’ve been alive, is that it is everywhere. The problem that lies with that is that it will be everywhere for a very, very, very long time. Centuries. Upwards of 500 years, everywhere. In fact, the first pieces of plastic ever created are still, in some form, on the Earth, either still floating along the oceans, at the bottom of the sea, or ingested by a fish some decades back, and was more than likely that fish's demise. Plastic kills—that’s the other problem with it. It is everywhere. You probably couldn’t move a couple few feet without becoming aware of a plastic in some form or another. Your garbage can sitting outside is made of it, your water bottle, even the one you’ve been using now that you take along to the gym every morning, is likely plastic. While it is reusable, it still is plastic, and it’ll be here long after you’ve gone from this Earth, and long after your kids and your kids' kids' kids have gone.