Basically; because it is one path. The central theme of Taoisme, Shinto, Boeddhisme, Confucianism is about your true self and its connection with reality, the world, the universe. One way of finding that true self and that connection is through meditation, but there are other ways as well; from going on a pilgrimage to practicing the arts. One of those arts is Budo or in this case more in particular Aikido.
How could this possibly disturb you so much?
I didn't perceive Carsten to be disturbed in that. You realize, of course, that the taoist fighting arts are seriously deadly and make no bones about their purpose? They're not like aikido in that regard, but more like serious ken-jutsu. Once unleashed, serious damage is bound to happen.
People need to understand that once a human being decides on a course of serious violence, it requires serious strength to stop him or her, and make no mistake: it requires extreme power to stop such a person without injuring them. So aikido gives us a better philosophical and spiritual base than say bagua or xing yi. But without serious power behind it, that philosophy amounts to BS. And the seriously powerful bagua or xing yi artist always has the choice to destroy or to show mercy, so it might be better, for practical purposes, to study xing yi. In any case, saying we show mercy to someone is a joke if we don't have the capacity to destroy them, and most aikido people I've met talking about being merciful to an attacker...they're just jokers, to tell the truth.
Now, speaking of philosophy and spirituality, Morihei Ueshiba also spent countless hours in prayer, but I don't hear much about that from aikido people. I once posted a thread here called "The Power of Prayer," I think it was. It's been a few years ago, I guess. No one responded at all, if I recall correctly. But if an aikido person uses Ueshiba's statements on power to show that there is no need for power, why do they follow his art of "making people do what you want them to do," but they don't follow his practice of praying for hours each day? I submit that it can only be that, subconsciously at the very least, they do have a great desire for power. At the same time, the have a conscious belief that power is wrong. So they and their aikido become seriously conflicted, but rather than work it out in physical struggle, they form organizations and build up that kind of power, expressed mainly in deciding which rituals will be used and who will get or be denied rank.