I'm afraid you have inadvertently offended a lot people with your reasons for quitting. I believe your reasoning is sound, but is based off of too little good information, and too much misinformation. To that end, I'd like to provide a little more good information. I hope you'll take it under consideration, use it as a springboard for further private research, and make a sounder decision -- whether that be to leave aikido, or find a new dojo.
The founder of aikido, Ueshiba Morihei, did in fact have a rather unconventional belief system, even by Japanese standards. However, his aikido was based on an already existing martial art, Daito-ryu (Aiki-)Jujutsu. Ueshiba's beliefs were very private, and actually did not effect the physical practice
of his art, though it might have informed how he approached and refined the curriculum.
There is a famous story of a French student of Ueshiba's, named André Nocquet. I've quoted it below:
André Nocquet wrote:
[One day] I said to Ueshiba Sensei, “You are always praying, Ueshiba Sensei. Then aikido is a religion.” “No, that’s not true. Aikido is never a religion, but if you are a Christian, you will be a better Christian because of aikido. If you are a Buddhist, you will be a better Buddhist.” I thought it was an amazing response. I really liked his answer. Since he was a Japanese I was afraid he would say that Christianity was nothing. Ueshiba Sensei had a great deal of respect for Christ. I was living in a four-mat room in the dojo and he would knock on the door and enter. He would sit down beside me and there was a portrait of Jesus Christ. He would place his hands together in a gesture of respect. I asked him one day if there wasn’t a similarity between his prophecies and those of Christ. He answered, “Yes, because Jesus said his technique was love and I, Morihei, also say that my technique is love. Jesus created a religion, but I didn’t. Aikido is an art rather than a religion. But if you practice my aikido a great deal you will be a better Christian.” Then I asked, “Sensei should I remain a Christian?” He replied, “Yes, absolutely. You were raised as a Christian in France. Remain a Christian.” If he had told me to stop being a Christian and become a Buddhist, I would have been lost. My heart was full of Ueshiba Sensei because he had a vision of the entire world and that we were all his children. He called me his son.
Here we have an example of a Christian perspective, but the idea holds true even if you're an atheist. Ueshiba's spirituality was an integral part of his practice, but not part and parcel of his student's
practice. In fact, the majority of his Japanese students did not subscribe to his brand of spirituality, including his own son.
The majority of aikido today trends along roughly three or so basic lines, created or focused by students of Ueshiba, none of whom believed in Ueshiba's spirituality as he himself believed it.
One of these lines is the Yoshinkai (also known by the name of its headquarters dojo, the Yoshinkan). The Yoshinkai trains Japan's riot police and female police officers. It's founder, Shioda Gozo, respected Ueshiba as a man and as a martial artist, but did not ascribe to his particular brand of spirituality. It's known for being a very practical style. There are others like it, and others that focus more on internal power.
Your dojo said they are aligning themselves with the Ueshiba's spirituality. That is, frankly, rather weird, and not typical of 99% of the aikido dojo out there. You suggest that another dojo will have the same spiritual concepts, only looked at differently. That is not true. In the vast majority of aikido dojo, Ueshiba's spirituality is not important, except in the broad strokes of non-aggression, altruism, and mutual cooperation. As the above story indicates, Ueshiba did not believe his spirituality was necessary for others to practice aikido, and so most of his students, and their students, did not, and do not.
If you enjoyed the physical practice of aikido, then you should give another dojo a shot. There are many flavors, many styles, and one of them will probably fit you. One of the greatest aspects of aikido is that it can be many things to many people.