if it was so obvious to most of us, we wouldn't be having this problem.

I do agree that it’s obvious in the way that you describe. But I still think it’s a point worth making—that it could apply to anyone. Because I don’t think that thought is likely to occur to a lot of people, regardless of their particular belief of choice. And that is a problem.

One can’t say that proposition is obvious to the population at large. Else, “we” (as in Earth in 2026) would have very political dynamics. So maybe Banksy felt inclined to do a public service announcement.

> I would expect more people to be aware of this

You'd be very surprised.