Stop destroying Syria by funding violent Syrian "rebels."

Before the United States engages in further military action, I want you to answer my question: The Syrian government has been fighting AGAINST all terrorist groups in Syria, since the beginning of the war, including ISIS, Al Nusra Front, Al Aqsa brigade and the people the US calls "moderate Syrian rebels". The "moderate Syrian rebels" fought WITH those terrorist organizations, welcoming them into Syria, fighting alongside them against the Syrian government. Why isn't the US government partnering WITH the Syrian government , instead of continuing to give arms to the rebels, who originally passed them on to radical Islamists, creating this problem in the first place? Also, if the US government believes that the power vacuum created by the fight between the Syrian government and the "moderate rebels" allowed the Islamic State to form and grow powerful, why would US policy be to create even more chaos by further arming the "moderate rebels"? The Syrian government is in control of over 70% of the country, wouldn't it be against our interests to further destabilize the country by sending more arms to the opposition?