I agree that it's a bit stupid to blame one person, whether Pitt or Greenspan for the stock market bubble. The inflated stock market of the 1990's was created by all of us, everyone playing the market.
Blaming one person for it is like pigging out on candy and cake at a party, and then when you get sick from eating too much candy blaming the parent who hosted the party for having allowed you to eat the candy. Even in spite of the fact that the parent you are blaming now had tried to warn you all you would get sick if you didn't stop, but you didn't want to stop, and now have the nerve to fault him for not warning you strongly enough.
We're all grownups here, we should start acting like it and take responsibility for our own actions.
What I am willing to blame Pitt for, at least partly, is the dumb daytrading rules which are in my opinion dumb and unfair and non-helpful, as well as dumb. Also they are dumb.