I'm very happy this is an independent topic now. I condsider myself an amateur theologian and love robust and positive conversation about spirituality, world religions and the sort.
I love O-Sensei's quote here from "Memoir from the Master":
"When anybody asks is my Aiki budo principles are taken from religion, I say "No." My true budo principles enlighten religions and lead them to completion."
http://www.aikiweb.com/general/memoir.html
I feel this is true, not just for Aikido but for any budo. That this is a Universal truth. A martial discipline will help in a religious endevour.
I myself am not religious but am a Spiritualist. I am an ordained minister of a Universal Faith "church". I find that the philosophy of Aikido is one of many paths to seek Enlightenment and it is very steeped in common sense.
I consider dojo to be a sacred place; outside of the secular and profane world. I respect the Japanese culture and tradition. It's so different from my American culture. I find dojo culture to be equally fascinating. This is all new to me and I welcome it with open hands and arms.
I can only find conflict of religion and Aikido if the Aikidoka
chooses to bring religion into dojo with them. I do not think there is violation of religion in practicing Aikido because dojo is a sacred space unto itself and the Aikidoka assumes resonsibilty for assimilating a different culture in order to learn. Can one learn Aikido without the culture...it becomes a bit "perverted" if so. It becomes purely a self-defense class. The spiritual aspect of Aikido is for me its greatest strength. All lessons learned on the mat are philosophical.
It's all a matter of learning "MASAKATSU AGATSU".
This is all IMHO, BTW.