Yo, hang the hell on.
Peter, I read a lot of your posts and like a good deal of what you have to say, but dude, it seems like you're rather flying off the handle at someone for something which, if you wanted to help him, you could probably give FAR more supportive guidance on. "aggression, anger - these are the dark side" or something, come on man. chill out, or be supportive and not damning with what you say. umm, unless you're his instructor; then be pissed off if you want.
So, when I first read the original post it actually struck something of a chord with me. not because i have problems with my sensei or his manner (next to my dad, he's probably the guy who i admire and respect the most in the world for goodness sake), but more because I took the question to mean something rather different than that.
The original question was, is the "spiritual essense of Aikido oftenly ignored by those who teach it?" Most peope so far have taken this to mean "most instructors don't teach about spirituality on the mat during class," I understood it to mean "we're supposed to be learning about how to find all this peace and harmony and junk within ourselves, but my instructor's a total combative jackass - what's the deal?"
It was pointed out to me recently that while many people will be senior to you in Aikido, not all of them will necessarily know more about life than you do. I think this is a fair statement. The question of "why is that guy so technically mature but so spiritually barren" is a fair one to ask, especially about one's instructor.
I will say to complement this last question that people often run into a danger of ideological essentialism with things like aikido, where personal development is an aspect and (sometimes) an expectation. Often we will expect someone who has trained for x amount of time or gained y rank to be internally developed to a certain standard as well, and we forget that everyone who is training is still a human "work in progress." Osensei said that he still felt like a beginner when he was in his 80s; are we small minded enough to think that he was only talking about technique? Surely someone as wise and humble as he was would not think "i'm spiritually complete;" it was (i'm reasoning) more a totalic statement than a technical one. i think that in this Osensei gives us a good lesson, of not expecting unreasonable things from our training partners or instructors, since we are all beginners anyway.
I will say as well that it can be tempting to think "if he's such a jerk, how the hell did he ever get promoted," and it's in these situations that we really must remember to trust that our instructors can make decisions for their own reasons and that their priorities that may exceed our conceptions; maybe he sees something in the 'jerk' that you don't and is giving him a chance to grow. and that's the gift we got, right? a chance to grow, and a direction to grow in?