I'm under 60. I'm cool and a role model to some people, and would be considered extremely uncool by very many others.
AFAIK, the Kardashians are a family in which one member has large buttocks and became famous for this, maybe through a reality TV show, and the rest are famous for being relatives of the one with the big butt. They then all had their own show, or something like that?
MM - I'd assumed that was 'mass media' in the OP. I've never heard of Mollie Mae, nor Tommy Fury, though I've learned from posts about that the two were a thing and have broken up. Fury isn't a common surname... is Tommy related to Tyson?
I don't pretend to know very little about most celebrities, I genuinely know very little about many celebrities. It's an aspect of who I am, something I'm comfortable with, and not something I feel the need to broadcast, though if someone tries to engage me in conversation or elicit my views about a celebrity I know little or nothing about, I'll simply let them know I've nothing to contribute to the discussion as I know naff all about the person. I wouldn't comment 'Who?' on social media posts about celebrities, as I'm generally not seeing social media posts about celebrities.
It's actually very easy to avoid knowing much about many celebrities if you have no interest in them - social media algorithms don't present me with Kardashian or Mollie Mae content, and I don't seek it out. Celebrity news isn't a topic of conversation where I work or amongst my friends, so there's no social driver for me to learn this stuff, and my kids generally don't mention celebrities at home at present, though that may change as they get older. My eldest has heard of Andrew Tate in school lessons; I was already aware of some of Mr Tate's views and we've looked at some of his content together and talked about it.
We do pretty well for niche knowledge about people we've mostly never met when it comes to sports stars, for a small subset of sports and nationalities. My eldest was genuinely amazed a few years ago to discover that none of their friends knew who the people who won the Olympics in their favourite sport. We took that opportunity to re-iterate that people are individuals, families are all different, not every family does the same things as us or likes the same things as us, and that's reflected in who and what people know about. They no longer find it impossible to imagine that people can exist in very different information environments and consume very different content, and understand that this is reflected in what they do and don't know about about.