Pararealist:
Yes, I understood what you mean. Actually I like this approach to not to try to convince everyone about our own "superior" beliefs. I am on your side here.

But I found it only a bit unfitting to this special case, where someone tries to convince other people to ignore environment pollution. And you tell him that people will learn this lesson with time.
I am more thinking that people will learn a lesson the other way around when they cannot bath in the rivers any more, when they cannot catch any fish in the same rivers, when the air smells bad and when you have dust around you like a thick smog.
Maybe this is not so evident in big countries like US, China or Russia. But here in Europe we already experienced a lot of this.