> critical and ethical outlets like the Washington Post.
This is an absurd characterization of the WaPo. Journalism, particularly at the highest level, is about power. It's about trading editorial positions and floating bullshit stories citing anonymous sources in exchange for insider access to (and financial partnerships with) powerful people and organizations, and advance leaks of their decisions.
Musk has decided that he's deriving no benefit from this traditional relationship. He already has the contacts in government because he is both a contractor and otherwise works in heavily subsidized industries, and also employs a lot of scientists who are employed as often by government as by industry. He doesn't need reporters to influence politicians or the public. His stock price is more likely to move (medium-term) based on tweets and press releases than any WaPo article, whose effects won't last out the week and are an opportunity to buy. These outlets have no authority, or leverage.
Musk realizes that he should be treated with kid gloves like any other major government contractor, ignored when not being defended or hailed. He's the girl. If an outlet chooses to start kissing his ass, that outlet will get all the inside scoops they can handle. Just pretend he's Raytheon.
edit: the press maintains its power by putting powerful people on pedestals, not on pikes. The way you get power is through powerful sponsors. Alienating the powerful gets you censored out of existence.