Very very true. But, I feel the answer is the same.
Advertisers are spending money for ads and they of course want the best possible return for their money and this involves as much tracking and intelligence-gathering as is technically possible. If one is now creating an advertising-supported site, you are now at the whims of advertisers.
There are alternatives, but I've never seen them scale. For example some independent blogs and other content creators have "hand picked" ads from selected partners. For example, DaringFireball.net runs one ad per week and he appears to work carefully with advertisers to select ads he feels comfortable running. But I've never seen this scaled up very far.
