Technically, hundreds of thousands of people own the world. You might be one of them, if you consider that most employers have blackrock in 401k, pensions, or mutual funds.
I think blackrock is actually less insidious than your standard investment banks like Goldman or Morgan Stanley or credit suisse because it's composed of normal people and obviously some rich ones.
I've personally used their Asia funds in my portfolio so that I don't have to do legwork on which Chinese companies are legit. I have considered their REITs but they don't earn enough for me