EDIT: Sorry, this came off a bit too personally. I'm a teacher too and I got angry when I read this story. I'll just say more generically that it is easily possible (and justifiable) for a student to feel alienated after a situation like this, especially if they feel like their educator didn't stand up for them. Whether or not "standing up for them" involves canceling the entire trip is a contextual issue, and I really don't know if it would have been a good idea in this case.