I don't see this thread filling up with lots of past 'handles'.
Three words: Chain of evidence.
Well, two words and a conjunctiv- never mind. The point is, there are plenty of people who, as the years pass, decide that for one reason or another, they don't really WANT people to see what their 10 year younger self wrote. Maybe CowboyX doesn't want people to know that as a teenager, he wrote Star Trek slash. Maybe OGzWallace doesn't want his hot blooded defense of Osama Bin Laden in the late 1990s to come up, and so on.
With search engines the way they are today, the amount of dirt on any of us is pretty stunning. There's probably lots of stuff you can't even remember typing that you'd cringe at if it came to light.