Nobody is talking about giving away ssh passwords: this is about a tool that Facebook has provides that helps you find friends that are already in your (Gmail) address book. Heck, just 3 posts above the OP says that he even temporarily changed his Gmail password.
The problem being described is a shady side-feature of this tool, where it apparantly stores all your contacts in your address book, even the ones not on Facebook, and when one of those email addresses ever pop up in the future, it is being re-used again. That isn't really nice if you're not up-front about it.
And you can't compare Facebook with a stranger in this context, it's a big company with a public image to maintain.
The problem being described is a shady side-feature of this tool, where it apparantly stores all your contacts in your address book, even the ones not on Facebook, and when one of those email addresses ever pop up in the future, it is being re-used again. That isn't really nice if you're not up-front about it.
And you can't compare Facebook with a stranger in this context, it's a big company with a public image to maintain.