If someone wants to make a point about racism they should call the perpetrators racists. If they want to talk about people with a sense of entitlement, they should call them entitled. The 'Karen' trope is too general to be meaningful, and designed to close down older women.
I mostly see it used against women who tell young mothers that their children should be physically punished ('warm her butt' and so on) on FB reels showing toddlers having tantrums. The answers, 'shut up, Karen' are as offensive as the comments themselves. Neither side is listening to the other, and both are writing off whole groups of people for seeing things differently from one another - a bit like words such as 'Remoaners' and 'Gammons' - it's like watching children shouting insults at one another instead of discussing the issue.
Speaking in cliches copied from the media cheapens debate and stops people from thinking things through, whether that is about 'Karens', 'gammons' the economy 'falling off a cliff', the NHS being 'on its knees' or whatever. It's lazy and tiresome.
In this case, picking a name that is more common in women of a certain age is also ageist and sexist, and 'Karenist', as people with that name are no more or less likely to be any of the things of which they are accused.
Karens can find hope in the fact that we don't hear of people being called a 'Wally', or a 'Herbert' any more, though - it will fade in time, and another name will probably be hijacked by the hard of thinking.