Humans are the most adaptable invasive species. The whole ocean can turn to jelly mush before we care. We will say "oh dear", switch our fast food order to fried chicken instead of fish and carry on as usual.
We're adaptable, sure. But we're not some collective. There are hundreds of millions of peoples lives that are tied up in the ocean. There are entire cultures. Those things don't adapt easily. Turn the ocean into plastic mush, and while I in my literal New York ivory tower will be fine, the fishermen will starve.