Middle and high school are full of stupid misconceptions about girls. In my middle school, people believed that if you wore black panties, it meant you're DTF. The boys also thought that if a girl's nipples were hard, it meant she was turned on. No amount of saying, "Bruh, it's just winter," or asking why boys' nipples don't get hard when they're horny, would change their minds.

It all really boils down to - some boys will grasp at anything to confirm their belief that a girl is interested in sex.