Did I say I thought that?
In theory, it should be apolitical. But that would mean all of them would have to refrain from making any comment on anything related to politics. Doesn't happen now and likely never will happen.
That said, I wouldn't target anyone, senior officer on not. But, if they appear to have crossed the line they might as well retire because they go no further if I have any control. Since POTUS approval is involved for ranks of Colonel (or Captain) or higher, they would need to be particularly careful.