To you it might be but I'm not gonna lie and say that I would want anything to do with anyone that was involved with Chang indirectly even if I was in Ed's shoes.
It's BS to you cuz you might not totally understand but if I heard that my friend or acquaintance had indirectly helped or notified my enemy then I would not be happy and of course it just had to be that guy that was used.
It's unfortunate but if Ed needs to move on, he needs to do it knowing that Chang and anyone else that's associated with him will be out of his life.
It's his choice, not ours. Besides, that guy's curiosity led to a whole new pain for Ed, personally I wouldn't forgive him either. The guy had a right to satisfy his curiosity and Ed also has the right to cut him off. ╮( ̄▽ ̄)╭
It sounds cruel but I don't know how else to put it, that guy needs to forgive himself for his mistake not look for Ed to ease his guilt.

Why do you not want to see him again!! He did nothing wrong ! TF