The fact that Selena's slowest Selena album is WTSGD (while she is dating JB) just blows that excuse of out of the water.
Demi who they deem superior still can't sell over Selena just shows the likability of their fav and who people prefer.

And this isnt brand new. It's been like this from Day 1. WTSGD will probably outsell Demi's first album lbr. And people buy it b/c they like it. Sales is a good testament to what/who people prefer.