It didn't get cleared, it's just that moderation history didn't get implemented until 2008.
As for the poll, there are only two reasons I can think of why it's even a question in the first place.
1. Some user made a request to get back a clean moderation history, so said proposal was made a site-wide question if it should be done.
2. The mod team came up with the idea themselves because of the second/third to last paragraph in this post:
The idea here would be to arrange a mod team that has only members with clean moderation histories, i.e. the perfect role models.
I voted 'no' in the poll.
This is simply my way of gauging interest in the idea. I'll have several polls like this leading up to E3.