Rooted in what? Not trying to argue or be mean here, it's just..

I like big men.
Heavy men.. something to hold onto not some bony or rock hard body.
Everyone has a type and they tend to soapbox that type.
Not everyone wants kids either so there's no need to woo woo yourself into imagining why that hard butt is fertile.

It's a shame. There's so many people to love.