Or like those protecting a loved ones at the expense of their own life, or ones who would rather die than convert to a religion not their own. Like those who would die to expose a lie, or to aid a cause they believe in. Or, ironically, those who would die for having failed to live up to their own ideals.
--To me those all seem irrational causes to care for to the point of staking one's life.
[But to Lucifer, the fact that there's ~~genuine caring~~ involved ranks it higher than what Sebastian's doing...? That's so strange.]