Actually, the Obama's move on pipelines was a stupid one from an ecological standpoint. There are generally two ways to move oil, pipelines and ships. Pipelines break less frequently and have a comparatively insignificant impact on the environment even when they do break. If a ship crashes, though, hundreds of miles of coastline will be impacted and requires a major cleanup that is both expensive and extremely environmentally damaging. Pipelines are, environmentally, a very clean and safe way to transport oil. Shipping, not so much.
And you'd better believe that if the US doesn't buy Canada's oil, Canada will just ship it to China. This isn't a choice between pumping oil or not pumping oil, it's a choice between a pipeline or shipping it to China. Since shipping it has much bigger environmental risks, the pipelines to America are the cleaner choice.
The reason Obama cancelled the pipeline is pure politics. He needs the green groups for the next election, and they're just as ignorant as you seem to be. He tried to delay the program so he could get the environmental vote, then approve the program after the election, but the Republicans forced his hand on the issue and he decided that votes were more important than the environmental impact.
So next time, do a bit of research before you start bashing people over stuff like this.