But elves are right. No matter how kind and good is dungeon master as person, the problem is they end up as either mental unstable or most likely outright insane and consumed by demon's influence. At least as we know it. Maybe there are other rules and exceptions, but it's too risky to put it to the test. Negotiation with DM could work or not, cause DM most likely won't give up on their most precious dreams and desires. And I guess elves don't want to gamble in potentially world threatening situation.