Classrooms are there for students to learn. ChatGPT just spits out an answer and doesn't really help with learning (and makes the student worse off). Why should it be allowed in the classroom?
This 100% could NOT be further from the truth. My 11-year old daughter uses ChatGPT daily and it is best teacher and the best tutor she's ever had. You are assuming that kids will (and their parent will allow) use ChatGPT to simply put in their HW and get answers. If used properly it is an invaluable tool for children and every child who doesn't use it will be at a huge disadvantage...
she will frequently go "I do not understand this still, can you try to explain this in another way" over and over for some concept(s) she is struggling with (last one was related to permutations)