Because Unarmed is fun! Early on it might be not so good as you have to make do with nothing or a boxing glove that would quickly wear out, but mid game when you get perks like Super Slam, slayer, and piercing strike, you became an unstoppable force.
Very likely they also don’t know or not know how to express themselves when around adult, so they take the question as “what do you like that i might like?” and their default answer is “i don’t know”. I’m like that back then(and even now), i do have interest but most are ankle deep, so i don’t really sure if i’m into it or not and not sure if other like it or not.