Your peers were being rational, but it's a drop in the bucket. I've come to the conclusion that privacy can only be protected with legislation. There is too much surface area to protect for the average person to police their own data trail online. Even experts have a tough time doing it. You'd have to abstain from virtually everything, and even then you can't keep other people from posting you, tagging you, etc.
This isn't a technical issue. It's a political issue.
This isn't a technical issue. It's a political issue.