It’s called absurdity. It’s funny because it’s obviously not true, and also funny because of the undertones that it’s a clever way to get horny teenagers to study physics who really just want to see the photos.
You are being pedantic, but I’ll play along. Absurd has multiple meanings. It can mean nonsensical, but it can also mean utterly ridiculous or silly. Under those other meanings I believe the pop-star-physics-professor still qualifies.
It sounds pedantic, but "absurd" is fundamentally different from "rare". A lot of baggage comes from flagging something as absurd, instead of just unexpected or uncommon. Winning the lottery isn't absurd, having 3 pairs of some chromosome isn't either, and being a successful pop singer with an academic background isn't either, it's just rare.
