See "Exploited". This time, Alice's moral superiority has driven others away, refusing to choose any side but their own.
Good and evil are defined because The Powers That Be are brainwashing people to be good or evil.
Because everyone is either pure good or pure evil. Therefore if they aren't 100% heroic and do mundane every-day things instead of saving lives, they mustbe evil. And your average joe does mundane things instead saving people and thus must be evil and not worth saving.
Since Heel Face Turns require there to be some good in the person beforehand to inspire them to make the change and Face Heel Turns require the person to be selfish or cruel enough to be capable of turning evil. And everyone is either 100% good or evil, their moral alignments are set in stone and thus they are unable to change and grow as people.