It’s not because she’s pretty, per se. Lots of women are pretty but no one would ever think of comparing them to a pole dancer.
I personally have never knowingly actually seen a real stripper or pole dancer, so I don’t know what they look like IRL. But I do know that this young woman could easily be cast as one in the typical TV show/movie. And she chose her personal style.
So I don’t find the clerk’s retort about touching up her roots out of line, at least not after Britt let loose with the personal insults.
That said, I criticize her for her bad behavior, not for her style choices, although I don’t like them either.