Or just plain ol' dumb. Really, an "old-fashioned" dude would probably think to himself "Hey, what are they getting from me to make all this work worth their while?" Having a conversation with someone about your favorite beer isn't going to be worth much unless they can sell your preferences to the brewer who makes a pint similar to your favorite brew. This shit is basic. Even the whole outrage over Cambridge Analytica seems ridiculous to me: why wouldn't a campaign spend millions on this data to target voters? It's not like they're telling people what to think; just what you want to hear.
Simply put, Zuckerberg did what any good businessman would do, he exploited people's carelessness to make a buck or two, and he did it with their tacit approval.