I think that it really depends on how much the religion is screwing the government. Muslims from secular lands (for instance Kazakhstan) are usually chill. Muslims from theocracies (for instance Saudi Arabia) often aren't. Christians from secular countries (say, Spain) are usually chill. Christians from the land of fundies (Uganda) are not.

The 6/10 is there because a casual believer is indistinguishable from a nonbeliever in most cases. Muslims are noticeably different, and so you notice them easier, thus giving you better statistics.

I should note that my thoughts on the matter are mostly based on anecdotal evidence and that you shouldn't treat my words as Itmām al-hujjah (heh).