Ok, I have never, ever heard a defense use this. In fact all I've ever heard/seen is the exact opposite (almost every home defensive team has tried to "get the crowd up and loud" on key 3rd downs).
So, I have a theory, it is either one of the two items - please vote:
1) This is a clever ploy by our defensive coaching staff and players to get the home crowds to make noise when their team is on offense during all of our upcoming road trips. Man, these guys think of everything.
OR
2) This is our defensive players actually saying that our defense is too complex and they just want to play. However, they know publicly criticizing our coaches is a quick way to be riding the pine.
You make the call.