Brittany Spears sold millions of records and sold out arenas everywhere. Does that make her music good, or substantive? If record sales are the measuring stick of "good music" then there are a bunch of "geniuses" out there you couldn't pay me to listen to: Bon Jovi, Poison, Journey.
That's akin to saying that John Grisham's predictable, cookie-cutter novels are "literature" because he sells a lot of them.
What part of “from a marketing standpoint” was unclear? Even at that, it’s okay for people to have different tastes in music. Really, it is. His record sales stand whether you like it or not. BTW, my three jock, adult, white male brothers all have a copy of this album. So, it’s not all kids, chicks and gays and minorities. They all happen to know just a little bit about music, too.