Why are cookie-based demographic-targeting ads that manipulate public opinion bad, while demographic-targeting ads on television, in magazines, etc, are fine? Is it because more targeted ad spend is more efficient?

If your problem is that advertising is used to manipulate public opinion - consider - why do we even allow political campaigns and paid speech? Its only purpose is to manipulate public opinion, and to trick stupid voters into voting for bad people.

I'm afraid your position is not entirely ideologically consistent with how we determine what kind of political speech is allowed, and is not allowed.