I feel like a major point of the monk is to interact differently with the combat system. The classic unarmed monk specifically does not use weapons, but can do way more damage than everyone else with unarmed strikes. They don't use weapons and their fists don't count as a weapon.
It's not about not letting you somehow make your fists magical (which is a monk trait anyway; also I think a quest to somehow make your fists have other magical properties is awesome), it's about not letting spells and abilities that affect weapons also affect the monk's fist.