Well, his guesstimate is closer to how is actually was than how it is now.
		
		
	 
His guesstimate is also stupid and irrelevant.  
 
A QB uses the weapons he has at his disposal, and competes against the weapons the defense has at theirs.  If the argument is that the league wasn't yet using the best athletes available because 1/4 of the population wasn't yet fully integrated into the league, then guess what?  That was true for Unitas's targets just as much as it was for the defenses he put his numbers up against.
If the argument is that his numbers mean less because the league was smaller, that's also idiotic.  A larger league dilutes talent, not amplifies it.  Unitas was playing against Pro-Bowl level defensive backfields and LB's every game -- just as his competition was.  And he was running laps around them.
The only thing that makes any sense to devalue in a smaller league is titles.  Which you can devalue by the appropriate mathematical amount and he still got way more than his fair share.
There's a reason Kook-Aid guy is universally recognized as one of the least intelligent posters on the board.  This kind of thing is that reason.