@ampersand As far as I can tell a) the pilot can kick anyone they like off the plane but b) doing so may be (and in this case was) in breach of the conditions of carriage & c) WTF? Injuring an old man is more important than upping your measly offer of flight vouchers to $1200 cash on the nail? *Someone* would have taken up that offer...
IOW sure: there’s a weasely technical way in which that interpretation is true & a zillion ways in which that’s completely irrelevant.