Nonsense, this is a reality across cultural and temporal boundaries.
And as an aside, a child could easily walk in on their parents doing the "do" and "ape" that behavior and never see "pop culture."
You are making something quite innocent(in the minds of the children) into something sinister. Even my girlfriend knew of a girl who was less than 2 years old that incessantly touched herself. It's not from any "pop culture" but from some rudimentary sexuality or physical sensation.
And it doesn't mean that EVERY child experiences or knows of these things at that age or before puberty. But if some do, it need not be anything sinister or for you to overreact to.
I came up in an age long before heavy sexuality on TV or in movies and somehow experimented as a child in a basic sense.
I grew up to be fine and adults were never a factor in any of this.
You want a sexualized youth and you reject my own, empirical eyewitness evidence. Fine. The modern world is yours.
For parents who want to avoid the damage you deny - but that is very real, shoot your TV and homeschool your children. Choose their friends carefully. Trust no one. Pray often.