As someone who has subscribed to the WP on and off for over 35 years, this is a big, f*cking surprise. You can bet that it will make news on the airwaves and in the halls of Congress. It is going to be quoted many times over the next few days by those supporting McCrystal's position.
Apparently, you haven't been looking too closely at the editorial page during those 35 years. This is no surprise (f*cking or otherwise) but part of a long pattern. Here is only one example e.g. the Washington Post's editorial from January 1991 supporting the Congressional resolution authoring George H.W. Bush to go to war. I'll bet you dollars to donuts that the WP also initially supported the Kosovo crusade as well as the Vietnam War. I don't recall right now weather it initially supported the second Iraq War but believe it did.