I think your misreading the sentence. He's talking about the skill sets they've shown in their title defences. As in, GSP and Brock are mostly wrestlers and Lyoto and Silva are predominantly strikers, whereas BJ has shown submissions and standup redularly in his career.
Okay then we're just going to act like Silva didn't submit Lutter and Henderson? And that GSP didn't submit Hughes twice and Trigg? Seriously? They both have a very well rounded game. Anderson's striking is light years ahead of BJ's and his BJJ is very good, too. GSP wrecked BJ standing, has FAR better wrestling than BJ and has a decent submission game, just prefers to control and GnP.
Sorry but the dude's all over BJ's nuts, no way should BJ be ranked over either of those two men, especially since one of them beat him, decisively at that.
EDIT: I'm not saying BJ shouldn't be ranked P4P at all, but I have him at 4th overall after Fedor, Anderson and GSP.