[Redbob]

"Islam has religious, legal, political, economic, social, and military components. The religious component is a beard [sic!] for all of the other components."

I'm sure the [sic!] comment was not in Dr. Hammond's original text: by inserting it, you're seeming to indicate that you don't understand that his usage of the term "beard" is correct...

[annalex]

It sounds odd in an excerpt, that’s all. Yes, that is probably a metaphor for “disguise”.