Geez man, you wrote a bunch... I'll try to reply succinctly.
Well, let's start off with some history shall we? The US is known to support proxy factions to do its dirty wills out of national (personal) interest; this was seen in Afghanistan, when US funded the Taliban, tor resist Soviet influence in the region. At some point before 911, then president Bush negotiated with Al-Qaeda/Taliban for a deal; twin towers, for a reason to invade Afghanistan.
For Osama, the destruction in the center of NYC would be devastating blow to the American spirit, and would give his militant group credibility in the world. For the US, it gave the American public the initial motivation to go into the Middle East, and reason for the militant group to understand that the US were victims, not the aggressors in this case.
Following the initial push into the Middle East, Bush used the excuse of 'WMD's' to prolong the war in the Middle East, and to complete his father's duty where he failed; topple Saddam Hussein. After Saddam's regime fell, the oil reserves of the country was in Bush's hands, given that the entire Bush family is well connected in the oil industry, it made the Bush family rich overnight.
Now since the Americans created a power vacuum in Iraq, where the Iraqi Army was poorly trained and greedy, they were no match for rebel fighters who fight for a cause; their will is iron strong. Al-Qaeda in Iraq eventually went through a rename, and the name ISIS we are all so familiar now was created.
Now, given that Assad is an enemy of the US, the American government/regime saw a golden opportunity to use its friend and foe, to once again carry out its dirty business. "A revealing light on how we got here has now been shone by
a recently declassified secret US intelligence report, written in August 2012, which uncannily predicts – and effectively welcomes – the prospect of a “Salafist principality” in eastern Syria and an al-Qaida-controlled Islamic state in Syria and Iraq."
Now the truth emerges: how the US fuelled the rise of Isis in Syria and Iraq | Seumas Milne | Comment is free | The Guardian
However, you underestimated the psychological grip these guys had over the people. Eventually, the little known group took over your Free Syria Army rebels whom you are also supporting, so essentially, your support went directly to ISIS.
So there you have it, you effectively created your friend you can't live without so long Assad is still alive, and your foe whom is becoming a pest to deal with.
America, you're playing with fire here.
Oh, and boots on the ground would be a start. Don't you think it'd be of the slightest decency for you to at least participate in a war which you guys fueled?