It's all part of the cult of personality. "We're all a family." Remind me, when was the last time your father just cut out half of the family?
But the thing is that people being cut off aren’t part of the cult anymore. Starting the conversation with the in group name is not just bad form, it probably also starts the rest of the people wondering if that name means anything anymore.
Maybe nobody is actually a Plaid except the board members. The rest of us are merely The Help, being coddled to extract more concessions from us.
When I worked at Amazon, it was all "Amazonians" like I'm supposed to feel some kind of kinship with the 1 million+ people who work there. Plus the cheap branded clothing. Ugh.