[Wissa]

The PIC does not become in charge till the plane starts moving under its own power for purpose of flight.

I think I've read articles in the past where pilots have ordered the removal of middle eastern appearing passengers speaking Arabic, acting suspicious, and making the other passengers nervous.

[TexasGator]

“I think I’ve read articles in the past where pilots have ordered the removal of middle eastern appearing passengers speaking Arabic, acting suspicious, and making the other passengers nervous. “

Depends on company policy. He may refuse to move the plane until certain passengers are removed but officially he is not PIC till he starts moving the aircraft for flight.