I think I (mostly) agree with you on this, with one caveat: network effects. If my friends and family and local businesses and community groups all use Facebook to organize events, plan socialization, announce things... I'm sort of trapped into using Facebook, because there's no alternate way to get that information! Now, I've done the cost/benefit analysis myself and actually ditched Facebook a couple of years ago. But that gives me even more insight into just how many things I
can't do because I don't use Facebook.
Perhaps a better comparison would be a multiple choice test that's a requirement to do something you really want to do -- scuba diving, or renting a bike to ride around a national park, something like that. Sure, it's not essential. But it sounds fun, and you could question the necessity of the test in the first place. But the test needs you to submit your name, birthdate, address, and answer a bunch of personal questions about your interests before you can do the fun thing. At some point, you feel like you're being taken advantage of.