The real answer here is this is a proxy war with Russia. We keep getting involved and trying to dictate the outcome to ensure the Russians don't get to influence the outcome to their benefit.
ISIS is currently seizing territory from Syria and Iraq. Why not let the Syrian and Iraqi armies deal with them rather than attempting to do so ourselves? If certain opposition militia groups need to be armed or funded to put down the uprising, why can't other regional powers do that rather than the US? After all, they have a lot more at stake? Every time we go into the middle East and attempt to own the problem and dictate the outcome, it comes back to haunt us. We end up supporting governments or rebel groups that are hostile to the US while making ourselves the object of their hatred.
People keep saying this, but only Saddam has invaded another country and tried take over their oil. We have many enemies in that region, but most of them, including the two largest Islamic powers (Iran and Saudi Arabia) haven't invaded anyone and Israel is our ally. So, unless some dictator tries to invade another country, I think we need to stay out of it and just defend ourselves from foreign attack.
There's a big difference between facilitating a coup and doing nothing. Was a coup really the only option?
Meanwhile, our obsession with opposing the Russians on every front has led us down a lot of disastrous paths. Nearly every communist regime that aligned itself with the Soviets has since fallen, including many former Soviet Republics, and that was accomplished via economic sanctions and political alliances, not war. Meanwhile, each time we've intervened militarily, it has led to something worse. Conducting a coup on the Iranian PM led to that country eventually becoming a radical Islamic state rather than a secular democracy. Arming and funding the Mujahedin rebels in Afghanistan led to the creation of Al Qaeda whereas our desperate attempts to prevent a communist regime led to the creation of the Taliban. Forcing a secular dictator like Saddam out of power has plunged Iraq into a sectarian struggle among the Sunnis, Shiites, and Kurds. Our actions are the reason the country is now overrun with ISIS terrorists and its the reason Iran is poised to significantly increase its influence. Our desperate efforts to oppose Assad (a key Russian ally) in Syria, led to us arming and training the wrong rebels, many of whom later turned out to be ISIS, while the moderate rebels have only been weakened. Likewise, are Libya or Egypt really better off now than they were under Gaddafi and Mubarak?
Every time we take military action to fix what we think is a bad situation in the Middle East/North Africa, it turns out worse, and if we don't learn from our mistakes, we are doomed to repeat them.