We don't want to believe what we deeply understand: nothing is really deleted, and someone, somewhere can (and probably will) use that record against us.
It's possible that someone and somewhere will be a Customs and Border Protection agent at a US airport, as by now we've all heard a story of how has prevented a few unlucky souls from entering the USA – after spending hours or days in a holding cell – because of some post or other activity that someone decided made them unfit to cross the border.
Now that's it's happening, what can we do?
The idea that we could onymously broadcast our opinions to the whole world, to be archived forever, and not have them used against us was naive in the first place.
Anonymously + Onerously?