Why do you assume this woman was bigoted and not just ignorant but acting in good faith?
She got weird vibes from him but at least tried to make conversation with the guy to get a better read on him.
The men who did 9/11 were Arab Muslims. Arab Muslims commit terrorist attacks somewhere in the world every day (though most of their victims are other Muslims). This is actually real, even though it's uncomfortable to acknowledge.
The woman was ignorant and that's on her but also a failure of public education to some extent. See something say something is an extremely valuable tool in preventing terrorist attacks so we should be more careful in considering the motivations of people who see something and say something.