i've seen this a lot. i'm going to guess it's a twofold problem.

1) the people that the liberal parties and ad agencies hire to "represent young people" come from highly privileged backgrounds. the process, from start to finish, never leaves an upper class prism. the result is that the political system only understands wealthy young people, rather than young people.

2) the whole thing upholds the media bias, which goes to reinforce the advertising bias. a circular loop of self-fulfilling delusion, if you will.

it really serves to demonstrate how out of touch the system is. they think that paris hilton is the average young person in which to model their shit off of.

http://www.theatlantic.com/politics/archive/2013/11/what-the-brosurance-and-creepy-uncle-sam-ads-dont-get-about-millennials/281667/