Oddly enough, I always knew what that phrase meant.
So, according to Cena, at the "P-P-V, Taker beat Vince blind because Vince was to busy judging John Cena to see the real Cena?"
Eh, why the hell not.
No in this case he was making a play on words and saying that Vince was beat blind...therefore he can't see him. It has a double meaning so he just used it as a figure of speech this time.
In other words it makes since because in Cena's rap Vince has been beaten blind...so in this case he really can't see him, but that's not what it always means.