So I don't know the inner workings of the pendulum stroke, eh? LOL, I guess I'm the ignorant yokel, huh? I was introduced to the pendulum stroke very early as part of learning snooker. I found it very unnatural and counter productive for me. I'm aware of the fact that you can manipulate the hands and wrists to get a more level cue action, using a fixed elbow. I just don't see how that is any better or less complex than a normal cue action. And if you don't do this, you WILL dig your tip into the cloth with a pendulum stroke, it's just the nature of the beast.
Anyway, those people teaching no elbow drop, are they misinformed? Depends on what you mean by that. Are they out of touch with what nearly every pro is doing? IMO, yes they are. One day I'd like to see a statistic of some sort, not just a few randomly selected individuals but a really large list of pros, short stops, and A+ players the world over. I think it would be pretty conclusive in favor of the elbow drop. Why is that, do you think? Please don't say because of ignorance. I think the actual ignorant people are the ones casually dismissing the aquired knowledge of people devoting their life to the game.
People who teach a pendulum swing have a system in their teaching, built on a philosophy of "fewest possible moving parts", with which I am in near total disagreement. Humans are not robots, and our muscles are not built for this kind of movement. We are built for flowing motions, not rigid back and forth, using only a pair of muscles. This creates a very unnatural feeling stroke and movement of this sort is likely to cause discomfort and even injuries. Luckily the pool cue is so light that injuries are unlikely in our sport, but it is not out of the question if you do this kind of thing every day for decades. No other athlete uses this principle apart from maybe marksmen, but they don't have to propel their projectile with their muscles.