The problem may be with how you are presenting Aikido and what others consider what spirituality is. The below excerpt is from the Wikipedia on Spirituality
"Whilst the terms spirituality and religion both relate to a search for an Absolute or God, and thus have much overlap, there are also characteristic differences in their usage. Religion implies a particular faith tradition that includes acceptance of a metaphysical or supernatural reality;:22, whereas spirituality is not necessarily bound to any particular religious tradition. Thus William Irwin Thompson suggest that "religion is the form spirituality takes in civilization."
Those who speak of spirituality outside of religion often define themselves as "spiritual but not religious" and generally believe in the existence of different "spiritual paths," emphasizing the importance of finding one's own individual path to spirituality. According to one poll, about 24% of the United States population identifies itself as spiritual but not religious.
Even though Aikido may have some spirituality meaning to you, don't present it that way. Aikido is a martial art and presents the benefits of physical activity as well as social aspects of peaceful conflict resolution with certain forms of contentions.