One's faith is deeply personal. If asked a question about my own, I'll answer it, but I will neither prosetylize, nor will I play the "My religion is truth/better than yours" game, which does nothing except promote hard feelings.
I think most people understand and respect this and think the same way. So by not pressing thanks for every pro-Muslim comment, it doesn't mean people are afraid or not approving... it is their way of saying "I will not encourage excesses in this category of posting."
Does that make sense?