Beating an Undead Horse

The Black Mist has condemned a lot of innocent people to unfathomable suffering. It's also condemned a number of horses. We get another look at the Iron Order in the new color story with Kalista and Ledros. To her credit, Kalista goes after the spearmen with the horses just dying as a side effect:

Leaping from a blackened rock, she twisted in the air and drove her spear down into the rider’s chest, banishing him to darkness.

One of the knights was hurled from his saddle, a glowing spear impaling him. His steed turned to smoke as he hit the ground.

Ledros...doesn't.

Ledros slammed his heavy shield into the steed of the first, knocking the spectral beast to the ground...

He struck through the neck of the knight’s steed, a blow that would have decapitated the beast had it been made of flesh and bone. Instead, it exploded into nothing with a keening scream.

So these poor horses keep repeatedly and painfully dying for the sake of vengeance against the people who ride them. That's a real rough deal for an animal that's already naturally skittish and that has no concept of morality.

To say nothing of Hecarim's horse. It's got a whole guy fused to it!