Your ideas might be right, Steelwhirl, and they can be arguments for his cranky and hostile behavior. My point is - there are hardly sources in the story itself about your thoughts.
I don't insist on Windkin being a "nice" character - I would embrace him with joy as an ambivalent character - even as the coming villian ... if only the story would show us some well-founded development.
Up to now it's all left to the reader's imagination and goodwill to find causalities and/or excusions. This way I could even find some mitigating circumstances for Zey's ruthless raid!
Nothing personal, Steelwhirl ... and, strange enough, normally I am the one to find venial reasons for bad decisions (at least when I take the commiter's point of view).