Well, because it would expedite and encourage increased burning of "the dirtiest oil in the world" by means of "the most environmentally destructive project in the world," and would tip us over the edge into true climate catastrophe.
FACT SHEETS & OTHER BRIEF INFORMATIONAL SOURCES
Keystone XL: Exports, Not Energy Security
NWF, 2 page sheet showing the industry's intention to export the oil.
Keystone XL: In Their Own Words
Sierra Club, 5 page collection of revealing statements by Keystone XL proponents.
Keystone XL: The Linchpin for Future Tar Sands Development.
NWF, 2 page sheet on how the industry sees the pipeline as critical to further expanding their operations.
Keystone XL: Myths vs Facts
NWF, 3 pages.
Keystone XL Pipeline
National Wildlife Federation, 2 page fact sheet.
Keystone XL: Tar Sands Pipeline Timeline
350.org. 4 page timeline..
Keystone XL in context: Oil sands and environmental management Pembina Institute, September, 2013. 4 page overview of the dubious environmental (mis)management of the oil sands.
Crude Behavior: TransCanada, Enbridge, and the Tar Sands Industry's Tarnished Legacy. Overview of a report (see below) about years of bullying and environmental destruction.
Keystone XL Pipeline.
National Wildlife Federation overview.
Keystone XL Facts
Tar Sands Action fact sheet.
PIPELINE NEWS & ANALYSIS ON THE KEYSTONE XL PIPELINE
MORE DETAILED ANALYSES
Crude Behavior: TransCanada, Enbridge, and the Tar Sands Industry’s Tarnished Legacy. NWF, 2010, 20 page report.
Global Warming’s Terrifying New Math.
Bill McKibben. Rolling Stone. 19 July 2012. Analysis of what happens if unconventional fossil fuels are extracted and burned..
Is the Keystone XL Pipeline the "Stonewall" of the Climate Movement? Bill McKibben, 7 April 2013.
The President and the Pipeline: The campaign to make the Keystone XL the test of Obama’s resolve on climate change.
New Yorker 16 September 2013. Analysis of the politics of the pipeline.
Staying Hooked on Dirty Fuel: Why Canadian Tar Sands Pipelines Are a Bad Bet for the United States. NWF, 2010. 20 page report.