Why not? The entire point of market economics is to make that not a problem and leave room for other potentially better companies to take the place of worse one

Why not? The entire point of market economics is to make that not a problem and leave room for other potentially better companies to take the place of worse ones. He obviously is a negative influence for the business as a whole even if he stayed out of politics, just the fact that he tries to pull so much money/value out of those businesses for personal gain has a negative effect on how efficient and beneficial to consumers those businesses can be.