1- I saw nothing wrong with the pictures posted, so I had to read the article... okay, taking cues from adult clothing to make kid-appropriate clothing is an age-old tradition. But applying it in the same manner as the adult clothing is NOT. The pictures in the articles did not show any bras, which is definitely a wildly inappropriate thing. The pictures in the articles look much like the JC Penny magazine pictures I used to see as a kid. However, the article said that there were many poses that mimicked adult poses... to which I say, what child HASN'T mimicked the adult poses in magazines? Also, the article said there were poses like that in the bras with pearls and lace... yeah, that's a definite NO!
2- many parents let their kids rule them. That's not to excuse there being this sort of thing, or to excuse those parents, just a reminder that the parent might have no control over what the kid is wearing. But yeah, parents who do have any measure of control over what the kid wears should be shot for letting their kids dress sexy.
3- the term was apparently loungerie, an attempt at a play on words. The point behind it was for "undies the kids can lounge around in."
As a kid, I would wear something that mimicked a sports bra for much the same reason I like to wear sports bras on their own as an adult- it's hot out and they're a perfectly acceptable top in public that doesn't make me sweat (as much). But pushup bras, or sexy bras... no.