Why was this removed by r/assam mods???

So, today in my sister’s art class (she’s in class 9, by the way), during one of the periods, the teacher was explaining something to her in Assamese, and they were conversing when one of her classmates said, “Wow, you speak Assamese!” To which she replied, “Of course.” Then the teacher asked why she is not Assamese or something like that, and she replied, “No, I am Bodo.” The teacher started exclaiming that Bodo is Assamese. She said, “No, I am from Assam, but my mother tongue is Bodo; I’m not Assamese.” He then started screaming, which made all the classmates look back. He said, “Then go to Bodoland; why are you here? Go back. People living in Nepal are Nepali, people in Bengal are Bengali; you go back to Bodoland; don’t come here.” Of course, she didn’t say anything; she was quiet, and then he proceeded with his class. My sister narrated the whole story to me, and I felt really bad for her. She’s just 14-15, and saying things like that will make her distant from her own culture, affect her self esteem and what not. Sadly, this is still happening even in a good school.