His comment is rhetorically partisan, but you haven't come close to establishing with evidence that it's "alarmist". I'd direct your attention to Eliot Cohen's essay in The Atlantic from this morning:
https://www.theatlantic.com/politics/archive/2017/01/a-clari...
Cohen is no liberal; he cofounded PNAC and served as a deputy under Rice in the Bush administration. And his take on Trump's last week is even more urgent than the parent comment's.
It is in fact not normal at all for the President's "chief strategist" --- an informal, non-confirmable role, created to house someone who stood a decent chance of washing out of Senate confirmation --- to replace the Chairman of the Joint Chiefs, the Secretary of Energy, and the Director of National Intelligence on the NSC PC.
Someone watching this unfold dispassionately might be forgiven for coming to the conclusion that Bannon is there because he doesn't trust Trump alone in a room by himself with a bunch of actual adults; Trump is, as has been reported for over a decade, famously impressionable.