Whatever is said on the topic, dancing is a spectacle. Force someone untrained to make a spectacle of themselves, and prepare for embarrassment and anger, and potential resentment. We -generally- don't like to get things wrong, especially in front of others, and so accordingly minimize the chances of it happening. Ergo, no dancing.
The reason why, is probably because it is a formless expression of feelings pushed into a slew of incoherent movement. I am not bitter about dancing, I like dancing, foxtrot, tango, salsa, whatever. It is simply that there isn't any social protocol that defines what supposed modern "dancing" is supposed to be, and that freaks the hell out of a lot (possibly most) happily conventional guys. Sure we are happy being silly, alone with our partners and friends, but put it in a public place and all that intimate safety is removed.