I don't know the answer at all. I didn't watch the 60 minutes segment, but I did read the transcript and I've done a little other research, but so far all I really see are accusations and a bit of a phobia. So, let's look at the one thing that we know for sure. The schools seem to be successful at teaching math and science--two subjects that are weaknesses pretty much across the United State.
The things we don't know that probably bear further investigation are:
1. are the visas of overseas workers valid and necessary
2. is the Gulen group siphoning money from workers' paychecks
3. are the schools teaching Islam
There isn't anything wrong with an Islamic group running charter schools. Gulen himself seems to be a pretty tolerant guy, not a terrorist at all. He also wants interfaith dialogue. Seem like good things to me.
He believes that education is the answer to making the world a better place. I'm not sure that qualifies him as a demon.
So, until we have further evidence, I'd say innocent until proven guilty. I understand that there are concerns that need investigation, but let's not condemn these schools or the group until we actually have something really solid and that has been investigated and adjudicated by someone besides 60 minutes or the general public's irrational fears. It also appears that the loudest opponents also have anti-charter school ties. It's at least possible that some of this fear is a smoke screen to try to discredit the charter school movement as a whole.
If the worst is true, then by all means, let's shut this movement down, but if kids are not only learning math and science but also valuable lessons about self-discipline, tolerance and logic, we should probably at least give the benefit of the doubt--for now.