Maximum Heresy

So I was forced to sit through Rainbow Rocks the other night. That was a thing.
And it got me thinking in terms of canon: Why aren't they already rulers of the world? And what is there relation to the Wendigos?
Firstly, they are in the human world. Unless this "human" world is some alternate dimension only barely based on ours, then the entire history should be the same. If the Sirens were exiled a thousand years ago, that would put them right in the era of the Crusades, and an era of hate so strong that just the First Crusade would have given them enough energy to spread chaos forever. This completely ignores the wars and hatred that ruled the 17th, 18th, 19th, and 20th centuries. With such negative emotion, the Sirens would logically have enough power to easily rule over, if not just the planet, but a large sector of space.
Now we come to the biological portion. The Sirens feed off of negative emotion, while simultaneously spreading it. The Wendigo feed off of strife and hate, and the more they feed, the more those emotions rise. So, we have two analogous feeding styles. Perhaps the Sirens are aquatic Wendigo, or perhaps they are false life, a blend of pony and wendigo genetics.
In any case, it's more likely I'm overthinking this entire thing again.