Welcome to the endless memory of the internet, Flamedramon. SL is hardly unique in this regard. None of the forums I visit, professional or otherwise, allow me to bulk erase my posting history or change or merge identities. I've taken care to protect my RL identity by keeping some of my onine personas anonymous, but there's a fairly extensive history of my RL self online going all the way back to Usenet in 1993 (when I was 23). I was aware from the start that my mistakes would probably outlive me, so I tried to make as few as possible.
Unfortunately, there are people born into this new reality that haven't yet fully grasped the implications of a world that never forgets. And the World must come to terms with this. One reason we've generally got along together 'till now is that we forgive and forget, which was largely driven by forgetting. Now that we're losing that "ability", we may need to work harder on the "forgive".
Thanks for understanding.