This is IMO the fundamental problem with the Internet (particularly today, Twitter and Facebook): it doesn't forget. One of humanity's greatest strengths is that we forget. We forget slights made against us, we forget things we and others have said, and we move on with our lives. Otherwise it would be very difficult to live with each other.
We even have proof of this. Some people have perfect memories and never forget anything, and while some learn how to live with it, for others it is absolute hell. Social media has broken that contract for everyone, and we still haven't figured out that storing and indexing everything indefinitely is actually one of the worst decision tech companies have made.