Just remember that being too strict towards one side on the other led Kuwait Airways to drop the lucrative JFK LHR segment after it refused to transport an Israeli passenger.
Airlines, like any other transport mean, should me "neutral" and should equally cater everybody.
Not sure how this relates to this topic. But anyway, the US requires that all airlines check passenger ID's for security reasons. It happens that Kuwait doesn't politically recognize Israel, so for the crew, an Israeli passport was not a valid ID. The passenger decided not to produce another ID, even though he had one (a US passport)! This is not in defense on Kuwait Airways (I don't really care), but it's only fair to state the fact as is.
A300, A319, A320, A321, A332, A333, A343, A346, A388, B712, B734, B736, B737, B738, B744, B763, B772, B773, B788, F70, MD11, CRJ7, CRJ2, Q400, MD82, MD83, MD88, E145, E175, E190