1. It seems clear that if there wasn't for the US invasion of Iraq and removal of Saddam; there would be no ISIS, no jihadist group controlling important cities and great areas of land.
2. Similarly, the only way to stop ISIS from winning in the Middle East, and specifically in Syria, is to support Assad, as Russia has been doing. The idea of the West supporting a democratic third force against ISIS and Assad sounds like an illusion now. So... it should be the lesser of two evils, right?
And no matter how bad these dictators like Saddam and Assad might be, they don't tend to plot and fund murdering civilians in Europe or the US...
(also, Saddam's propaganda could be pretty crazy, and that makes it an amusing watch).