People seem to think one of three things about Elon Musk:
A) Musk is a typical rich asshole who only loves money. B) Musk is a typical power hungry asshole who loves power and money is a side effect. C) Musk is a big nerd who thinks he can solve big problems better than other people, and power and money are side effects.
I believe he's type C (Hopeful Nerd). So for that type of person, his positive return is solving the problem. He thinks he can fix social media. He thinks social media is a big problem. He thinks humans need to fix social media or they are fucked, just like if they don't get off oil they are fucked, and just like if they can't leave Earth they are fucked. Fundamentally, he does think humans are worth saving.
I would bet that the vast majority of people that choose to work with Elon believe he is type C (Hopeful Nerd) and believe in humanity as well. That's why they put up with all of his flaws and toxicity - because they believe in the cause and know it's a broken eggs == omelet situation.