Is Everyone in data science a mathematician

I come from a computer science background and I was discussing with a friend who comes from a math background and he was telling me that if a person dosent know why we use kl divergence instead of other divergence metrics or why we divide square root of d in the softmax for the attention paper , we shouldn't hire him , while I myself didn't know the answer and fell into a existential crisis and kinda had an imposter …

computer computer science data data science datascience divergence math metrics person science softmax square