I'd rather you looked at it this way: If Icahn has an incentive, then the company has a management problem. You might not like the outcomes of his investments, but hes top-notch at recognizing shortcomings in existing management and their own businesses.

For me, despite ever maybe owning 0.0000000000001% of a company, the power of mutual ownership means all perspectives are taken into account. And that generally means more accurate valuations, and therefore safer investments.