Before saying that the pax
could be legally asked to leave by crew - ask if he:
a) Knew that in advance (as very few pax know)
b) Was it explained to him that he
had to leave?
Both are highly unlikely.
We know that United Breaks Guitars: 2008
https://en.wikipedia.org/wiki/United_Breaks_Guitars
And we know that, after being told to stop taking pictures - and COMPLYING - another pax was thrown off: 2013
Thrown Off a United Airlines Flight for Taking Pictures! - Live and Let's Fly (thre is a follow on story link at the bottom of the page)
As to the CEO: he made a standard CEO first response based on what he was being told. He will be telling his people that, next time, they'd better tell him the full situation.
I don't think he should lose his job but the media can afford to try and unseat him as the outcome is win/win for them.
Both of these events happened before Munoz took control. What he needs to point out is that NO ONE learnt a DAMM THING.