If child labor is illegal, then why employing children to sell useless products and mass-brainwashing children/society as slave is legal?
Observe. Majority ads now employ kids for one or another way.
In 2008, an estimated 17 million children watched the Superbowl with their families. Alongside the football, they also watched a number of highly creative and engaging ads for beer and alcohol.
In India, kids watch IPL and condom ads together. In one of the multiplex in city (Inox group), toilet is covered with condom ads. You cannot go with kids to restrooms.
The marketing of adult entertainment to children has been, and continues to be, an ongoing issue between government regulators and various media industries. In a report released in 2000, the U.S. Federal Trade Commission (FTC) took movie, music and video games industries to task for routinely marketing violent entertainment to young children. Subsequent reports since then have shown that although advances have been made – particularly within the video game industry – there are still many outstanding concerns relating to the frequency that adult-oriented entertainment is marketed to children and the ease with which many under-age youth are able to access adult-rated games, movies and music.  Specific areas where the FTC is calling on entertainment media to improve on include restricting the marketing of mature-rated products to children, clearly and prominently disclosing rating information and restricting children’s access to mature-rated products at retail. 
Kids represent an important demographic to marketers because in addition to their own purchasing power (which is considerable) they influence their parents’ buying decisions and are the adult consumers of the future.
According to the 2008 YTV Kids and Tweens Report, kids influence:
Breakfast choices (97% of the time) and lunch choices (95% of the time).
Where to go for casual family meals (98% of the time) (with 34% of kids always having a say on the choice of casual restaurant).
Clothing purchases (95% of the time).
Software purchases (76% of the time) and computer purchases (60% of the time).
Family entertainment choices (98% of the time) and family trips and excursions (94% of the time). 
Fact 1: The average child sees nearly 40,000 commercials a year, about 110 a day. 
Fast 2: Children under seven are especially vulnerable to marketing messages. Research shows that they are unable to distinguish commercial motives from benign or benevolent motives. 
Fact 3: More and more Ads now demo Children with VETO power (Parents? Who are they to take out decision attitude)
When you apply common sense to fact 1,2,3 and paint a picture – you derive a ugly picture of society. Keep your family out of this trend/mess.
 Poulton, Terry. “ ‘Kidfulence’ on family spending strong: YTV Report.” Media in Canada. February 22, 2008.
 Kunkel, D. 2002 “Children and Television Advertising,” Handbook of Children and the Media. Eds. Singer, D., and Singer, J. Thousand Oaks, CA: Sage Publications.
 Federal Trade Commission (2009). FTC Renews Call to Entertainment Industry to Curb Marketing of Violent Entertainment to Children. http://www.narm.com/PDF/FTCReport_1209.pdf