There are obviously tons of disgruntled Delta passengers. If Saleh and his friend were removed solely for speaking Arabic, then they have a reason to be disgruntled. I get that people are cautious and afraid, especially when it comes to flying, but you can't remove passengers for speaking Arabic alone.
Apparently the guy who was thrown off a plane has a history of making "prank" videos where he tries to scare passengers, but that also doesn't make Delta any more justified in kicking him off the plane. It's a situation where everyone involved is a jerk, but Delta should know better.
The fact that the passenger was asked by the captain to leave their flight for the reason that he had a phone conversion on the phone and with his seat mate in Arabic and that made some other passengers "uncomfortable" is a valid issue. Airline travel should not be governed by "mob rule." If 20 passengers were upset by the use of Arabic THEY should have been given the option of getting off the plane. Not to force off the innocent party. Delta blew, and not the first time.
While it is possible for airline passengers to over-exaggerate their complaints, Delta Airlines also has a long history of mistreating and irritating their customers. The fact that this customer is disgruntled makes it likely that Delta Airlines did something to offend or anger him, and that he is not exaggerating.