Carl Icahn is obviously enjoying Twitter as much as everyone else. He just used his account to take another shot at his favorite punching bag, fellow activist investor Bill Ackman.
It's not immediately clear what New York Times article Icahn was referring to. There doesn't seem to be any story in the Times arguing that Ackman foibles prove something is wrong with activist investors.
There was, however, as story here at NetNet yesterday that made something close to that argument. And James Surowiecki made a similar argument in the New Yorker today.