How do you function without knowing the meaning of common words?
altruism (n): the principle or practice of unselfish concern for or devotion to the welfare of others
One can be altruistic, and still gain wealth. You may be claiming that he is only funding Gates foundation as this is the best means of producing more wealth, but that would take a severe misunderstanding of investing & economics.
Oh, and still waiting on that evidence that gates's foundation is suppressing local farming....