Sam Altman is almost certainly aware of the arguments and just doesn't agree with them. The OpenAI emails are helpful for background on this, but at least back when OpenAI was founded, Elon Musk seemed to take AI safety relatively seriously.

Elon Musk to Sam Teller - Apr 27, 2016 12:24 PM

History unequivocally illustrates that a powerful technology is a double-edged sword. It would be foolish to assume that AI, arguably the most powerful of all technologies, only has a single edge.

The recent example of Microsoft's AI chatbot shows how quickly it can turn incredibly negative. The wise course of action is to approach the advent of AI with caution and ensure that its power is widely distributed and not controlled by any one company or person.

That is why we created OpenAI.

They also had a specific AI safety team relatively early on, and mention explicitly the reasons in these emails:

• Put increasing effort into the safety/control problem, rather than the fig leaf you've noted in other institutions. It doesn't matter who wins if everyone dies. Related to this, we need to communicate a "better red than dead" outlook — we're trying to build safe AGI, and we're not willing to destroy the world in a down-to-the-wire race to do so.

They also explicitly reference this Slate Star Codex article, and I think Elon Musk follows Eliezer's twitter.

I don't know, but I would suspect that Sam Altman and other OpenAI staff have strong views in favor of what they're doing. Isn't there probably some existing commentary out there on what he thinks? I haven't checked. But also, it is problematic to assume that science is rational. It isn't, and many people often hold differing views up to and including the time that something becomes incontrovertibly established.

Further, an issue here is when someone has a strong conflict of interest. If a human is being paid millions of dollars per year to pursue their current course of action—buying vacation homes on every continent, living the most luxurious lifestyle imaginable—then it is going to be hard for them to be objective about serious criticisms. This is why I can't just go up to the Exxon Mobil CEO and say, 'Hey! Stop drilling, it's hurting the environment!' and expect them to do anything about it, even though it would be a completely non-controversial statement.