I've been reading and thinking about this very subject for many years. The hell of it is, they're partially right. Personal responsibility is all and well, but the advertisers are targeting children with very focussed campaigns. And the parents go along with it (witness the huge backlash I got when I pointed out that the woman freaking out at the airport because her kid was freaking out over a sippy cup might need to teach her kid that he can't always have whatever the hell he wants).

Your comment about manufactured, chemicalized foods goes there too — "personal responsibility" should be able to combat that too. But it can't always.

Yep, it's a combination of all those things. And involuntary overeating certainly seems to be one of the culprits (if advertising didn't work, it wouldn't be so ubiquitous). However, no quick fixes will fix that. These people are smart, sneaky, and motivated, and have a scary amount of political clout, so don't expect the politicians to actually fix anything (like you really would). They'll just do a lot of grandstanding like always.