It was the only road open to President Obama to regain, or retain, some of the hope he evoked in the American public that elected him.
After his hasty retreat from an Israel/AIPPAC confrontation and, mainly, his dismal handling of the Financial Crisis which ended with an outright CORPORATE USA victory over the American taxpayer and American pensioner both announcing a stupendous drawback of a vigorous, reformist and bold Obama Administration with great disillusionment in President Obama himself he had to stand up to the image that sent him to the White House in the first place.

Had he handled the Mac Chrystal affair in any other, conciliatory, way President Obama would have lost for good the bulk of those that sent him to the White House and ended as much of a disillusioned and ineffective retiree as ex President Carter is.

There is no reason to continue the war in Afghanistan-- except to protect the opium crop--which is the main reason the US is still there.