You are comparing HORSE behavior to HUMAN behavior at this point, and that is just...asinine.
Horses do no control a company where they need to make calculations and things only a HUMAN could do.
Horses do not go based on a good temper in the wild.
Horses do not think the way we humans do. That's where you're getting all over the place with your argument.
The mares fall under the protection of whatever stallion is in charge. The may initiate the forward movement, but he stays behind and 'herds' them. He protects them from behind.
Horses in captivity (otherwise known as 'tamed') may have instinct left (what horse doesn't?), but it still boils down to PECKING ORDER! Just because a mare is the 'dominant' one of the bunch does not mean she is the top dog, the leader, the one in charge.
Again, you are mixing up human behavior and emotions into this, and that only makes things worse for you. You seem to have it in your head that horses and humans think alike, well NEWS FLASH! We do not. We are two different species. We may form bonds and work well together at times, but there are also times where we do not.