Agree, yet it's not an either Mars or Earth question. Judging by priorities of corporations (making money, of course) it will certainly be both Mars and Earth.
In fact, the whole concept of "pollution" on Mars makes little sense. We could convert it to radioactive slag and plaster it with "Eat at Joe's" billboards, and it wouldn't hurt anyone or anything.
What we ought to be doing with Mars is terraforming it. I'd start by collecting extremophile bacteria from Earth and letting it loose on Mars and see if any of it takes hold.
