Right, I agree that this 'secret police' comparison is off.
But your Facebook/GMail comparison is different as well: They are not useful/popular because of user tracking, they provide us with a free and (limited..?) useful service. I'd argue that's a bad thing as well, but I'd separate multiple levels of evil tracking:
1) You track me to sell my data and to profit from the ads. I gain nothing (you might be very lucky to guess that I want X and therefor save me from having to type "Where to buy X" into Google, but I'd not consider that useful in general).
2) You provide a free service that I'd gladly use. You track information about me to make a living, pay the costs etc.
1) is unacceptable for me, although it tends to be largely ignored in general and considered normal.
2) is on the edge and I'd like you to at least tell me about your tracking and make me aware of the general data you're collecting. It's up to me to opt-in (by using the service and agreeing to this tracking) or going elsewhere.