And there is a difference between acknowledging it and causing a scene. Rank and file employees engaging in a political attempt to topple the CEO is certainly unprofessional. That level of manoeuvring is purposefully causing damage.
Criticism is healthy and should be respected. Even if it is "unprofessional", that doesn't give the company the right to just fire someone for that. If you would allow companies to fire their employees for criticism, that sounds a lot like a dictatorship to me.
Is there a line you would draw somewhere? Anywhere?
This equity stake gives you a vote for which you can use to influence the actions of the board and thus the CEO.
Being financially dependent on the company to provide employment by no means gives you power over the CEO. Of course, criticism is not black and white - but being an asshole CEO is not illegal, and putting yourself out to "fight the good fight" sounds good on paper, but do you no good at all.
I'm shocked at how many closeted authoritarians here on HN crawl out of the woodwork to defend Musk every time that he faces criticism for his dictatorial actions.