Interesting observation.

It stems from an observation that one usually qualifies a noun or noun phrase, it's usually to add information. So both chick flicks and action movies somehow depart from the prototypical motion picture. That is based on the assumption that what one is trying to do when uttering or writing something what one is up to is communication. Not only action flicks, but science fiction, horror, slasher, sports, spy, art flicks, and westerns, romantic comedies, musicals, documentaries, etc. (These are somehow all different from just the plain old movies.)

Ceci n'est pas un seing.