Let's get real. This was a pilot using authority granted to them for security purposes to punish somebody whose politics they disliked.
The pilot should be fired effective immediately.
It's interesting that you know what the pilot was doing and why they were doing it. Anyways, there's zero chance the pilot will be fired. Pilot unions are incredibly powerful and go to bat to protect their members.
How would the pilot know the perp's political leanings...?
edit: oh you mean the "f z" guy
I would be a bit more charitable in assigning motive for the pilot's actions.
Airline pilots are morally and physically responsibile for the lives on their aircraft. This necessitates respect for their authority.
Like other professionals, they must compartmentalize personal beliefs and professionalism.
Playful antics and silly BS, whether it be for the lulz, politics, or anything else, is a disrespectful act of defiance to the individuals you entrust to deliver you safely to your destination.
They are the final authority in flight, and have broad discretion they must exercise prudently with a bias for risk aversion.
I've known 2 airline pilots. They are the most even keeled people I've ever come across. Literally, the coolest and calmest people.
The system (should) weed out anyone who would act unprofessional, like letting their political beliefs cloud their judgment.