Yeah I can see why they're considered pure. The guy's only crime is being a sheltered idiot, even though he was married to the princess he didn't really participate in any way in messing up Raoul's life. He even seemed sincerely repentant for what little he may have done to screw Raoul by proxy.
Momma too was probably the only person in the entire series to do something completely selfless for the sake of a loved one, that already puts her at a higher standard that 99% of the world (even though the standard is so low its in hell lmao).
Since like chapter 30-something it was beginning to look obvious that Raoul was gonna pull a "XK-Class End-of-the-World Scenario" on the whole planet before he died, its kinda wild to think that he still had enough mercy in him to build a Noah's Ark for whatever good survivors are left.