The US government stuck to the position of "Assad must go" way longer than reasonable. Russia had warned early on that displacing Assad would mean supporting the extremists even before ISIS/ISIL showed up in the media.

Russia had obvious strategic reasons to support Assad but even to a neutral observer it should have been obvious supporting the rebels would be a bad idea as soon as the Islamists showed up and the dangerous consequences of the Arab Spring (i.e. destabilizing entire countries that were now democratically electing radical groups) became apparent.

The Nobel Peace prizes have a long story of that, beginning with Kissinger. And the EU and USA have been always supporters of any dictator that could help them till they think it's more interesting to throw away and usually it ends with everything in the area being worse for the people that live there.