I don't understand you.
Let's look at being "Environmentally Conscious" from this perspective:
Human beings live on ONE planet. It is the only place capable of providing us with air, food and water that we need to survive. The most critical resources -- reasonably unpolluted air and potable water -- are finite. That is a fact. Additionally, the most practical energy source (petroleum) is also finite.
At this point in time, and for the foreseeable immediate future, there are no other places where we can live. Period. That is just a simple fact.
Maybe in numerous generations intergalactic travel to seek new places to live that will provide us with the resources we need will be viable, but for now, nada.
How can being environmentally conscious be stupid? It is simply common sense to not wantonly waste and contaminate your limited, critical resources. No, they won't run out in our lifetimes, but the fact is things are going to become progressively worse for succeeding generations unless people get realistic. I honestly cannot think of anything more selfishly inconsiderate than leaving a depleted mess for the future to deal with simply because this generation chooses to ignore an unpleasant reality
You don't have to be a tree hugger to be pragmatic.