And, like ViHart, I tend to cynically assume that people are using their identities as an attention-getting tool.
Isn't that sorta the point though. Your identity is an expression of who you are, and the goal is not to express your identity in an empty room; you want others to see/understand/connect-to who you are as a person.
Don't get me wrong, I think the peope who feel the need to shout their identities are overbearing, annoying, and exhausting. But I also think we all want that attention that is human connection.