You are assuming that Google is even charging Obama for the ad space.
Only it doesn't work like that, not even close to that way. Just recall, out of the billion dollar Obama warchest, 800 million of it went to television and radio commercials. The amount of money they waste is astounding.. Well, that is, unless you consider how they blow through the public’s money.
So yes, target DNC ads, make them pay, and make them buy more for the most obscene things. Guys kissing for Obama, a ‘normal’ family of two women and one boy. Free abortions as a right! Condoms for kindergarteners! Sterilization for 13 year olds! Watch the campaign self destruct as they bury themselves in their liberal echo chamber and drown out any reasonable voice.
Because if you look at this year's DNC platform, it reads as one of the most radical agendas ever - none of that platform would win a popular vote in ANY state, even California. Let them hang themselves with it. Oh, and drain the unions of another billion dollars, diverting from their looting of the public dollar to support a doomed campaign.