Because it makes his friends money

One reason Bush gets away with the crap he does is that he is so audacious and so totally without limits that people can't quite get their heads around the fact that he's doing it. And the things that he does seem to make no sense at all, until you reason that it has nothing to do with principles, beliefs or ideology at all. He does whatever will line his friends' pockets (and his own, once he leaves office) and that's his only consideration.

Ozone Rules Weakened at Bush's Behest
EPA Scrambles To Justify Action

The Environmental Protection Agency weakened one part of its new limits on smog-forming ozone after an unusual last-minute intervention by President Bush, according to documents released by the EPA.

EPA officials initially tried to set a lower seasonal limit on ozone to protect wildlife, parks and farmland, as required under the law. While their proposal was less restrictive than what the EPA's scientific advisers had proposed, Bush overruled EPA officials and on Tuesday ordered the agency to increase the limit, according to the documents.

"It is unprecedented and an unlawful act of political interference for the president personally to override a decision that the Clean Air Act leaves exclusively to EPA's expert scientific judgment," said John Walke, clean-air director for the Natural Resources Defense Council.