You are correct that there are many issues that may be wrong with any/all presidents. I even have issues with Bush. But the issue was Obama's lack of a strong opposition to increased harm against Christians AND moderate Muslims.
But he did, and as a matter of fact he worked to get a coalition together to fight terrorism as he didn't like Bush's cowboy go-it-alone approach.
The Iranian deal also was a byproduct of this approach, and contrary to right-wing propaganda, it has been effective, which is why all the other nations that signed on have stayed and why our own intelligence say Iran is going by the agreement.
Many people blame Obama for pulling out of Syria, which in hindsight did lead to the expansion of ISIS, but most Americans wanted us out overwhelmingly so. How can we justify constant intervention in other areas of the world and not allow those that live there make some contributions, especially since they have far more irons in the fire than we do?
My comment about Assad was just that it was another example of a weak response. I think it would have been better for him not to have made "a line" than to have made "a line" and not respond to it when it is crossed.
Yes, that was very much a mistake on his part, so I'll cut him no slack on that.