If that's true, I bet it has more to do with what we consider "orthodox" when it comes to various forms of Christianity than to Islam.
I mean there's hardly a Christian to be found (outside the Vatican) that insists on wearing a particular hat for all public appearances, but that kind of thing is common in lots of religions. With Christian denominations, if you pray regularly, lots of people are already willing to describe you as orthodox; if you do it five times a day as a Muslim you might not be particularly devout.
I'm a-religious and not particularly interested in the subject but my wife's parents would be considered fairly orthodox Mennonites by most people...but the amount that the church is involved in their lives is slightly less than the involvement a good friend of mine who considers himself a lapsed Muslim has with his mosque. And I agree, he's pretty lapsed compared to when we met. But still, Islam plays a huge role in his life, larger even than the role of the church in the lives of a couple of people I generally think of as cult members.
There's a really pronounced double standard when it comes to Christianity vs other religions, I think.