Just stop. There are basic core tenants of Islam, regardless of sect or sub sect, that the vast majority simply agree with as that is what their book tells them. If they consider themselves Muslims, they must. Fundamentals are fundamentals. That the West takes our religion based on reformation and setting aside some of the more...strident...bits merely makes us less fundamentalist. It's up to them to say they're really not Muslims just as it has been up to us to reform past the old ways. The simple fact is most Muslims, to BE Muslim, believe in and agree with core principles. We should respect this instead of treating them as insincere or lesser people.