Some people just want to see you suffer

Since the beginning of the semester I know for a fact that I have no body odor because I have confirmed it with doctors, random people and a friend. However, there remains a few people in my class who persist with demonstrating with their body language (holding their nose and whispers) that they are smelling something. I can only theorize that it is to make themselves feel better about themselves. I know it is motivated by malicious intent and not out of insecurity or conformity because they were the only ones doing it despite people who had been seated closer to me not demonstrating the same body language. Mind you this is in college and a quite advanced course.