Totally agree. "Karen" is supposed to refer to a specific kind of person: an obnoxious, angry, entitled, and often racist middle-aged white woman who uses her privilege to get her way or police other people's behaviors.

However, it's often misused. It's used as a away of dismissing someone without genuine consideration. This dismissal makes it all the easier to misuse the term. There is no real defense against being called a "Karen" because only a "Karen" would object being called one.

BTW, I feel the same way about "mansplaining". It means something specific: a man talks condescendingly to someone (especially a woman) about something he has incomplete knowledge of, with the mistaken assumption that he knows more about it than the person he's talking to does. However, it too can be used to dismiss someone without genuine consideration.