I would disagree that all Disney restaurants are "kid friendly". Sure, most all of them (except Bistro de Paris) have children's menus and accept children (except Vic and Als), however I would not consider several of them "kid friendly". To me, kid friendly would mean that the restaurant is designed to stimulate and keep children entertained. Some examples of kid friendly restaurants in my opinion are WCC, Sci Fi, Prime Time 50, all of the character meals, Ohana, LTT, etc.
I think most, if not all, of the signature restauarants are not kid friendly. They are subdued and supposed to be quieter. I also wouldn't lable LeCellier, Grand Floridian Cafe, Concourse Steakhouse, Captian's Grill, Spoodles, Boma or Mama Melrose as kid friendly. Certainly children are welcome and most will do fine, but there aren't a lot of things to keep them busy and engaged. In restaurants like this children need to be restuarant friendly, meaning they need to be able sit nicely and eat a meal without yelling, screaming, crying, running around, or kicking and hitting the people next to them.