That may be true if your conception of people is limited to their role as consumers. But people are more than consumers. They are also citizens, moral agents, members of families, workers, conscious and experiencing subjectivities, biological entities with evolved neurophysiologies and psychologies, and so on. What is good for people as consumers may not be good for them considered from a different perspective.

And who's job is it to decide what's best for the people?

> They provide value to the consumer. They also are good for small businesses.

Apparently you believe that you should decide that. Which argument are you making? "Facebooks Ads are good" or "Even if they aren't good people should decide for themselves"?

Facebook decides that Ads are good for its users every time they show one. Either that or they know Ads are harmful but show them anyway.

It is perfectly easy to go through life without a Facebook account. Yet people choose to use it. This suggests to me that they feel they are getting some utility out of it.

People do all sorts of things that are bad for them. Sometimes by choice and sometimes because they don’t recognise the potential downsides.