Exactly; it's not that the young ideological think-they-are-doing-the-right-thing are not serving a corrupt system (perhaps unwittingly). They are effective because the corruption they serve diligently comes from the central party and not from local considerations?
Corruptible is relative to the goal you're trying to achieve.
If you're the king of a nation, anyone trying to convince your knights to overthrow you is a corrupting force. But at the same time you could be a brutal ruler corrupted by power, and it is the knights that are trying to upturn the corrupt system.
They won't do graft. They will follow orders. Even and especially when the orders are corrupt.