Ummm. So is the original poster then too. I didn't say I was a genius for figuring this out, I just never noticed it until somebody else pointed it out to me recently. I was just trying to help Big Chill figure out the answer to his question.
It's not all that obvious of a diss to Cube unless you knew about his label Street Knowledge, which I did, but not until some years after hearing Dre Day. I was 8 when Dre Day came out and it's actually the song that turned me on to rap, but I had no clue that Street Knowledge was Cube's label at the time.
It's especially not obvious when you consider that the song is mainly going at Eazy, and he was much more well known for wearing White Sox hats than Cube was so that's pretty easy to overlook. They don't have a Cube look-a-like in the video either yet they have Eazy, Jerry Heller, and Luke look-a-likes so once again I was only led to believe that those lines were dissing Eazy, and I bet a lot of people on this board made the same assumption I did.