the fact remains, at the base level, that anything that is called a martial art should and is grounded in a system of combat.
and yes, the art of loading and firing cannons is a martial art.
As Ellis Amdur notes, some folks (like me) are doing aikido with some infirmities and sharing what we can do with others who have infirmities, and I believe that is a good thing - but I have never led such a class for a single evening without being mindful of embodying to the best of my abilities, and sharing the key points as best I understand them, about the martial applications or principles our training is based on and pointing out some practical application of what we are doing.
When a student asks me a pointed question about why, from a practical defensive perspective, something is done this way rather than that way, if I can't demo it on the spot, we play with it for a while until it makes sense.
Otherwise, WTF are we doing while we work on posture, connection, kata, etc?!