It really isn't. It's just annoying when believers try to foist nonsense on you or justify their own assininity with vapient recitations of things other people have said in defense of their stupidity.
Religion is the last bastion of old world ignorance which hurts the entire world.
What is the abandonment of faith if not enlightenment?
Realistically faith isn't broken by an external influence. When you challenge someone's faith they fall back on the defense mechanisms they've been indoctrinated to use. Faith can only be overcome when the believer comes to his/ her own realization of its absurdity.
As for the reasons why eliminating faith would be desirable, the other posts here provide adequate answers.
Mostly the pure masochist joy of it...also it makes me feel better about the failures in my own life.
The purpose of life? To crush your enemies, see them driven before you, and to hear the lamentations of their women!