But they do, and it doesn't seem to bother them. So there's something going on you don't understand.
You have a basic problem: the world does not match your theoretical expectations. In the US, for example, the more religious and theistic the person the less likely they are to support environmental conservation, and vice versa - perhaps the most famous example was Reagan's Secretary of the Interior James Watt, but there is and has been no shortage of examples in positions of authority, now and in the past.
There is a faction of theists that is trying to promote a "stewardship" outlook, but they are having an uphill struggle.
The large influx of theists that has altered the demographics of so much of the most vulnerable ecological zones has set things back a bit - it takes a generation or two at least to get people from a theistic tradition up to speed, so to speak.
And so the environmental movement in the US has been largely atheistic and (to a lesser degree) areligious - unless you count that "nature mysticism" you find so far inferior to the great wisdom of the institutionalized monotheisms.