So because untrained people do something badly. You should train them to do something badly because it is more natural?
Ever thrown palm heels on pads? You can hurt your wrist there as well if the pad holder isn't up to speed.
Hit the bottom of a hand mitt when they angle it forwards and see what happens.
Hammer fists come with a different set of issues in that they take a bit to set up or they don't compete as well against straight striking.
you are very confused in your view. there is no logic in your statements at all. it is barely worth my time to respond because your view is so one dimensional. your contention is that a hammer fist doesnt compete as well as a straight punch. yes in competition that would be a correct view but we are not talking about an MMA competition we are talking about a self defense situation.
lets start with the fact that species are born with certain instinctual behaviors. scientifically this is called a "Fixed Action Pattern" (FAP) . these are actions that are triggered by certain stimuli called a "releaser" in the brain. a FAP is also defined by the fact that they improve with repeated use. so a baby is born with a FAP to suckle. in test studies you can put a squirrel in a cage with no contact with other squirrel's and given a pure liquid diet from birth and if you give that squirrel a nut he will know what to do with it. in the same way a hammer fist strike is a FAP. the genus homo species and other apes have been doing this action for millions of years.
it works quite well. biomechanically it is the most powerfull striking action someone can do that is a FAP. a straight punch is a learnt behavior and takes a lot of skill to generate power. where the hammer fist incorporates the core contractions and arm muscle contractions that pull toward the body which are very strong a straight punch requires mass and rotation to achieve the same outcome. if we look at the structure of the body the bicep is stronger than the tricep. the pulling action has direct force incorporated by the stomach muscles and the latissimus dorsi.
so what does that mean? it means that an untrained person can generate more force with a hammer fist because it uses larger muscle groups while a straight punch needs more coordination to move the body as a unit, a skill they have not yet acquired and would need more time to develop. A FAP also can get better with use but at a much faster rate then a learnt behavior.
your comment again about what works in an MMA event is irrelevant. a straight punch holds the advantage not because of some ill perceived "set up" time lag in a hammer strike but because of the human eyes and the ability to perceive the strike. a linear strike is not as well picked up by the eye thus has a better success rate in competition. however you an take any boxer MMA guy or anyone you choose and when a life threatening event happens .....lets say a tiger grabs a hold of your leg and you need to strike it to let go, your brain will be more inclined to revert back to the hammer strike. your comment is also predicated on a standing position. you should know that when you are on your back that straight punch fails and a hammer strike still maintains some viability. the hammer strike is functionable from many positions and angles where a straight punch does not.
lets do a test , sit on an straight back chair and throw some straight punches on a hand pad, now have the pad held in the horizontal position and use the hammer fist. what strike has more power? in most self defense situations the victim is not defending themselves in the standing up right position squared off with their assailant.
with the gross motor movements of the hammer fist there is also crossover applicabilty. if someone has you around waist from the front (like a tackle) the most available strike is the downward elbow and guess what this is the same gross motor acting but on a shorter stroke. place a rock in the hand same motor action, a stick, a purse, a book, a laptop computer and you will be striking with the same gross motor action as a hammer fist strike. why do you think we call it a hammer strike, because it is the same action as using the tool...a hammer. its a very efficient action as far as expenditure of energy for the return.
now you said something about doing it badly????? who is doing what badly? because humans do that action quite well with no training at all.