But it was okay when you idiomed somebody with the tired, 'okay boomer'. I see.
As Will Rogers mentioned, it's not what they call you, it's what you answer to.
Okay, doomer.
It's not "tired" to me. I only recently learned of it, and it most accurately encapsulated the response I felt that rant deserved.
I don't see how "Karen" fits at all. I've only seen it used, and then only recently, in context of feminists lecturing men regarding how bad men are.