Musk is vindictive. It looks like he's been gutting and/or attacking agencies that have or had investigations into his companies. USAID had been looking into Starlink in the Ukraine. The NLRB's probes into practices at Tesla. FAA and SpaceX. SEC and cryptocurrency. And so on.

As to motive, I think that it's less Mars and more money.

After gutting the responsible agencies, Elon will finally add payments to his X-everything app.

And then once that's done, and in the name of "efficiency", he's going to start filtering US government payments through X, including Social Security and Medicare (or, at least, what's left of them).

Thus ensuring he gets a cut of every transaction made from those accounts.

Who you start getting a cut out of every dollar the US government spends, who cares about Mars?