Dr. Dan,
I agree with you in theory, but not in outcome.
Yes, you are correct that right now only 10% or so of Muslims are active terrorists--the others don't have the guts to be, can't afford to quit their jobs, fly to Iraq, and strap on a suicide belt, have kids to take care of, etc., but that doesn't mean that practically all the others don't support it or wouldn't become terrorists under the right circumstances. I'm willing to bet that the overwhelming majority of American Muslims have sent at least one check to CAIR or Hamas.
I don't believe that 15-25% of Muslims are misled or secular and are good people. RIGHT NOW they may appear to be. At any point, especially in college when exposed to many more devout Muslim friends, they might become actual practicing Muslims. Even those who never make this change would always support their brothers and sisters in actual, all-out war. I wouldn't trust a single one of them.
If someone is really, truly a "phony Muslim", then they should leave this devil religion altogether.