"People aren't rational" is just a dishonest way of saying you disagree with someone's very logical reasoning due to different values.

I know Facebook is scum, but I have no other way to stay in touch with some of my IRL friends. So really I have competing agendas here, social connectivity vs. personal privacy, and I'm sacrificing some privacy to gain connectivity because I value one over the other. I, personally, mitigate the privacy loss by only sharing stuff I'd consider publishing publicly anyway, only liking stuff that's similar, avoiding groups and pages, periodically deleting all old content from my account, using adblockers and private browsing all the time, and customizing the FB web app via local scripts (thank you, FB Purity).

You can disagree with my values and the resulting choices (maybe you value personal privacy over social connectivity), but those choices are completely rational even for people who don't necessarily think about them in painful detail like I do.

So get over yourself and quit thinking that other people are somehow beneath you because they make different choices than you.