I think the missing info here is that Musk gave the non-profit the initial $100 million dollars, which they used to develop the technology purportedly for the benefit of the public, and then turned around and added a for-profit subsidiary where all the work is happening.
He has plenty of standing, but the "supposed to benefit all mankind" argument isn't it. If that were enough, everyone not holding stock in MSFT would have standing, and they don't.