Why do we 'destroy' stumps though? They give a resource in return for removing them, just like boulders, which have the 'chip stone' flower option. They aren't built structures, the best tool to remove them is a shovel, not a pick or sledgehammer (as potjeh pointed out).
The few friends I've actually convinced to play this game always get stumped by stumps. Their intuitive answer is to right click them just like trees, after that they try to use the 'dig' adventure action to remove stumps, and finally they ask me and i tell them 'use the destroy action, but make sure to use a shovel too'