The sudden catastrophe played right into the rancher's hands, but as Skylar said, Theoden is actually a fairly "benevolent" king.
At least he didn't shed a few crocodile tears and then grab a fan to put out fires, or chop up the burned cattle and sheep to put them in pies and eat them again.
The Green Forest Army was doing just that, and with Kelan's tacit approval no less.
It must be said, those who are full tend to eat with more dignity than those who are starving.
This of course has nothing to do with the nobility or baseness of bloodlines or souls, nor with justice or evil, but purely because their different ecological roles determine the roles they must play on a specific stage.
If a one-in-ten-thousand miracle really happened, and Kelan, supported by Chaos with twelve leaders, accomplished something big, his descendants might have a chance to become the new Theoden.
It's simple, just give them a few hundred years to fill their bellies like the Devalu family.
