You have a microscope don't you? Post up some close up pictures of this stem THC, I've never seen any. Usually stems have hairs that look a little like trichomes, but no heads form.
They actually taste quite nice, it's not a sour bitter flavour like hash, more of a herby flavour. They're good for adding a weedy flavour to drinks or food, or for chewing. Vaped bud has almost no taste, any little bit of non-vaped cannabis helps to give it some flavour & it tastes good with enough sugar.