Agree that pageants are sexualizing young girls. I can not see the video but if MM was twerking, then it was sexualized. Twerking is so the performer can show you, to be crude, how well they can pop that ass on your dick.
Before Netflix aired the ridiculous show "Cuties" there was Disney to sexualize their Mouseketeers. But not just them. Remember Brooke shields at 13freakingteen? Marketed like a ... a grown actress. Dakota Fanning too at least in one movie. And the One hit wonder Billy Ray could not wait to pimp out his daughter in every possible way.
It's really a societal sin and has been for a long time. Sure, they can say that teenaged boys needed something besides the Sears catalog for variety, but this wasn't just about teen age boys.