The biggest self-indictment in that post by POTUS was "I was always surprised Biden didn't do it!"

I am not surprised that Biden didn't cancel all SpaceX contracts for political reasons, neither are most rational people.

Trump doesn't believe that smart people with power can have ethics or morality because he doesn't have them himself.

It's not ethics or morality, it's just "not being a child." A president not personally retaliating against a critic doesn't need to have anything to do with ethics, it's just requires a post-middle-school mentality of "I may not be happy with this person but I [my country] can still benefit from things they do."

The property of "being a child" in an adult is effectively a matter of ethics and morality

No, it can be justified with rationality alone.

I phrased it poorly:

Being an adult child has moral and ethical consequences.

Behaviours and emotions that are totally legit and tolerated in a child are no longer so in an adult.

An adult that has all the privileges and freedoms of adulthood over childhood, like the ability to vote, drink, drive and hold an office, also has to abide by the moral obligations of being an adult.

But if you're rich enough (or poor enough, hah) nobody's gonna hold you to "adult behavior" standards. Is there really a moral or ethical aspect to "don't get into a shouting match on Twitter"? Or is it simply childish?

> But if you're rich enough [..] nobody's gonna hold you to "adult behavior" standards

but that's a problem, isn't it?

That's on us. Why on earth did we stop expecting adult behaviour from ultra-rich people?

Rational and ethical have a lot of overlap.