Walter Cronkite get his nose hairs clipped?

The author is exaggerating by creating an image of something that would be incredibly boring. Mr. Cronkite was a famous newscaster in the US known for this authoritative voice. Picture your grandfather clipping his nose hairs. I doubt the author knows anything about Mr. Cronkite's grooming habits.

Yeah, I know Mr. Cronkite is a very famous newscaster in the States. The author is a father who was urged by his 4-year-old daughter to play Barbies and comb the hair of the doll,
As a man he was not familiar with that sort of thing.
So I guess the author here use this sentence to express his imcompetent in playing dolls and his combing of Barbie's hair is very obsurb.

No, just like engineer said, he finds combing Barbies hair very boring, it has nothing to do with incompetence. He doesn't find playing with dolls to be all that much fun.
I have no idea what obsurb means.

By that word I meant "bizarre". Sorry it's a misspelling. I got your idea, but why did the auhtor mentioned Mr. Walter Cronkite?

He's exaggerating the point. Like engineer said, what would be more boring than watching a old guy get his nose hair trimmed? Walter Crokite is famous, so by referencing him, readers get to imagine a universally known old guy getting his nose hair trimmed, not a generic old man. It paints a stronger visual image.

Absurd.