You're right, no reason to get incensed about people being ignorant, at least, no more reason than normal.

However, the case here is my best argument for people who, when they ask, or I'm telling them about Internet security, respond, "Who would want my data? There's nothing interesting on there."

It's never that you're particularly interesting or important to other malicious users, it's that with disregard for the most minimal security precautions, you become a data point in their system. After that, it's a numbers game: among 100 million users, how many have made further bad decisions with their data (predictable usernames / email addresses, simple passwords, etc.).

Stuff like this exposes the fundamental flaw in Facebook's security model: you are only as secure as your friends are.