How the situation may have come about, does not change what is.
And what is, is what I have listed, and you can not refute - a string of “legitimate interests” - arguably the world’s greatest concentration of them. Outside of China/North Korea, it is currently the epicenter of geostrategic confrontation.
Your approach is apparently to simply retreat from any confrontation, unwilling to risk fighting, allowing any competitor or mortal enemy to expand at will, ignoring the future implications.
Regardless of how we got to this point, there is a lot to lose by simply throwing the region to the wolves, and burying our heads in the sand, wishing that it doesn’t matter.
Oh, I would think Iran would be a bet more important. But those who created this mess now use it as an excuse to continue, yet have no solution for it. What end result do you envision, and how will it be acheived? To me it seems Assad is the best of bad options. Or do you believe in the mythical moderate Muslim jihadists? Our meddling sure has done a great job in Libya.
BTW, any government in Syria will be hostile to Israel, bucause they hold the Golan Hts. While I understand and agree Israel was justified in taking them, and cannot give them up for security reasons, that doesn't change the fact that it guarantees a hostile Syria. But Israel can defend themselves against Syria. If they fall it will be because of the demographic reality that they are on their way to a Muslim majority sooner or later.
I’m not saying we retreat but I am saying that if we expect countries like Russia and China to respect our alliances then we have to respect theirs.
Right now we don’t have a moral leg to stand on if Russia were to start bombing Poland or some other country we’re allied with.