He said about people you've never met, and I'm paraphrasing, "If you know someone's name but not their face, or their face but not their name, then they're famous. When you know someone's face and their name, then they're a celebrity."
Most politicians would meet this test. They're famous because you either know their face or have heard their name, but you can't connect the two. When you can, they're celebrities, and there are few of those in the political world.
The same for people in the arts or sports. You've seen their face, or the name rings a bell, but only when you can put the two together, then they're celebrities. Sports and the arts have more celebrities than politics, not surprising.
Of course, people can become famous without any talent and then, later, celebrities with no talent. Plenty of so-called reality TV "stars" are celebrities.
Compare this with radio or the print media. You may listen to someone on the radio for years, or read them regularly in print, but you would not be able to pick them out of a crowd.
Ergo, they're famous, but not celebrities.
When I lived in New York and Los Angeles, I got to know some famous people, either by dancing at clubs or through friends of friends. It was amusing being around them sometimes, because if they had a famous name but an anonymous face, they were ordinary Joes and Janes.
Alternatively, particularly with actors, people would always say things like "aren't you that guy who was on that show with the alien puppet?" But no one ever knew their name.
I wouldn't mind being famous. But I'd never want to be a celebrity.