Martingales are useful and safe if you use them correctly. If they are too tight, and if a horse doesn't need one, then that's when you get into issues. You really shouldn't use a martingale just because everyone else is or it's part of a uniform. A martingale is just a tool, just like a crop, or spurs and should only be used when necessary. You wouldn't use a crop on a horse that's hard to slow down.
While I agree with you on your viewpoint on martingales, I would have to disagree about the crop. A crop does NOT tell your horse to go faster. It is a reinforcement of your leg. Just because a horse is fast does not mean that it is educated OR obedient to your leg.