I think he is over estimating how much of a significance he had, and ignoring the huge influx of people coming into the project due to some articles on prominent sites being published about Bitcoins.
Still, introducing a huge number of computers into the network was beneficial in a number of ways even from one person, and and it is interesting that somebody might even try to control more than 50% of the computers on the network at any given time. If anything, he did a huge service to the Bitcoins community as his "attack" came on-line just as many other people eager to do some real hacking came into the project too. So in a way, he didn't really attack the network but rather gave it some real protection against those who might have done even more harm.
The question is in terms of what is he going to be doing with all of the bitcoins that he "earned" from the attack?