It does sound like the student is witnessing calls for the elimination of Israel, which is (in my opinion) way too close to calls for genocide to be tolerated in a school. I'm not sure an art teacher can be faulted for not understanding the geography and history of the conflict well enough to recognize that the map is showing a Palestine displacing Israel, and the students that made the map probably don't understand that depicting Palestine displacing Israel is (I believe) reasonably understood as a call to genocide.