Carl C. Icahn was at Drexel University yesterday for a rare public address, standing before hundreds of LeBow College of Business graduates at their commencement.Icahn has won some praise for fighting for shareholders' interests in a climate that has turned more critical of corporate management. In keeping with his rhetoric over the years, his message to students yesterday contained no small amount of reverence for himself - though cloaked in some joking self-deprecation - and disdain for corporate America.