If it was a disciplinary issue (disrupting the class) you don’t lower a grade for that. Grades are supposed to be a measure of knowledge or how well the student meets the objectives. Geez, doesn’t this teacher have a clue? If I was the parent I would ask to see the teacher’s written objectives for the day and disciplinary plan. If the teacher didn’t say that grades would be lowered for classroom interruptions then he needs to explain himself.
And then he needs to take tolerance classes, to learn to be tolerant of cultures that differ from his own.
Your post is spot on. It he considered it disruptive, send him to the office or something, but grades shouldn’t be lowered over something like this.
I guess that it is okay to ‘Leave kids behind’, after all.