They may have been “magnanimous” only from a mechanical perspective, rather than any RP attribute or conviction. It’s a quirk that, perhaps paradoxically, seems to naturally end up pretty much maxed out as a result of reward-seeking gameplay. Heartless, on the other hand, is VERY hard to keep at a high level unless you very deliberately pursue it.
I had magnanimous maxed myself before I traded for about 120 clay labourers. Now I’m primarily subtle and daring.