Why? I don't really have anything that dangerous, illegal, or weird open... And the browser history on my local machine is at most exposed to me and my fiancé, who I don't really care to hide it away from.
As for specifics of why, that's something I've chosen to do and that's all that matters.
No obligation to share, certainly.
Curiosity is there in part because we may learn a valuable lesson - something those “with nothing to hide” [I know] might not’ve considered. (not a request, we can learn from others)