Thanks all for the help. It's not that I didn't know it was part of core or that the thought crossed my mind. The only thought on my mind was that I had installed comment karma at some point and that field was left over from the plugin which was not the case because the table that plugin creates is different.

So, I deleted something of core I thought was plugin related, that's all. And thanks to Stephen, I know why it screwed up the comment system.