If I were to start following you whenever you are going anywhere, sit next to you whereever I can, and write down as much about your life as I can, without asking you for permission first, would you also agree that that would be acceptable if I claimed that I need that information to operate or develop my business?
Also, obviously, noone "needs" that information, that's just bullshit. It may sometimes be helpful, but that doesn't mean you need it--just as any other business might be able to learn something from surveilling my non-online life, but that doesn't make it a need for them to spy on me, especially without my consent.
Whether you like targeted advertising is completely irrelevant, as noone is telling you that you may not agree to being spied on. That's like saying that there is nothing wrong with forcing everyone to walk around naked because some people enjoy appearing in porn.