It looks to me, based on what I know, that the members of ISIS are generally very bad people. Could the US successfully intervene to defeat the group's aims? I find it doubtful, but if in fact we could, I am not reflexively opposed to the idea of doing so.
But this idea of picking out particular "moderate" rebel groups and funding them just strikes me as ridiculous. But it is typical of our current politics: it expresses the felt need to "do something" about anything unsatisfactory in the world, while doing it without any real commitment or any real likelihood of success. It is based on the same sort of sentiment that regards NFL players wearing pink shoes for a month as an important step forward in curing breast cancer.