Because you had absolutely no reason to leave us but your selfish interest.
Yes, back when you were in Aeon I thought highly of you, then you just left.

I tried making you stay and I was devastated that you just left us like that.
(if I remember correctly, you didn't even for one second consider how the people in Aeon might feel if you just leave, at least that was my impression)

And while you say I make it sound like you detonated a Kitten-class nuclear superweapon, I'll have you consider that I treat this clan like my second family. Others might be able to shrug it off like that and give you a second chance, but it's going to take alot more to make me do the same.