Yes, ISIS was a product of US greed and hypocrisy but I don't believe they are still controlled by US. Decisions made by the US generally backfires them badly.
Of course US would rather bomb the Syrian Government troops to make their evil allies happy but that doesn't mean ISIS are not a threat to US.
ISIS would happily kill US citizens wherever they find. Though they take supplies from US, they are evil religious extremist in the end.
ISIS is still a threat for common US citizens, but we all know common human blood doesn't matter to the elites of US, It's just a business for them.