My entire family, with the exception of DW, has worked for or currently works for Disney, myself included (11 years with the Mouse in the 80's and 90's). Both my sisters worked for Disney (one still does, going on 32 years), my son did while in college, and my dad did too after he retired (loved the parks and worked Steam Trains and Main Street Vehicles part time). None of us ever had anything even remotely resembling an NDA. I've had several since of course.
To this day, if I share some exciting news I found on WDWNews, MiceChat, or some other site with the group, my sister invariably already knows about it, but just didn't bother to tell us. Even the return of the Electrical Parade with its new final float didn't get a heads-up from her, and we LOVE us some Electrical Parade.
I don't know what it is, whether it's just the culture of being part of the magic and wanting to maintain the surprise and wonder, general disinterest in sharing with outsiders (because CM's are a tight bunch like few others) or what, but I think for the rank and file CM's who aren't feeding a blogger or some other social media, they just aren't interested in blabbing. Especially if they've been asked not to. For many, having knowledge of what's behind the curtain and knowing few others have that knowledge is special, and an understood and cherished privilege.