The rental goats in Moria are absurd. Not their appearance, not how they get drunk and stuck on things: their use of mechanics is nonsensical. This is a standard thing in games: you get used to a mechanic in one case, then still accept it even when the context that made it coherent is gone.
In this case, the mechanic is “you cannot be attacked on rental mounts.” This makes sense as gameplay: that would suck, especially as you have no control at that point. In the early days of Dark Age of Camelot, there were horse routes that would kill people, because they took hills very sharply, and you were not flagged as immune to falling damage. Yeah. Anyway, throughout Shadows of Angmar™, you use the rental horses along roads. There are few to no enemies on the roads, and you can buy blowing by the occasional orc or bear on your Fast Horse. There are a few horse routes through dangerous areas, but they all use the fast travel mechanic: you teleport from one stable to the next, not seeing the monsters you must have dodged along the way. Immersion is preserved!
All that goes out the window in Moria. Except that Moria lacks windows. The goats ride directly through large camps of monsters, who ignore you because … because you’re on a goat. Right, orcs fear goats, or goats and their cargo are invisible to bats’ sonar, or…
You are standing there in Moria, starting a risky solo fight, and a rental goat silently zooms in and runs you over. It looks like some double-stacked warg rider just added to your fight, so panic! panic! Wait, no, it is another goat that somehow is immune to everything. But if you ride your own, identical goat, they are all over you.
Can I buy one of those invisible, invulnerable goats? How do they tell them apart?