Not that i have more time in this then you or others, or that ive figured out a (the) key, but i offer my take:
you said: "is it actually a generative, creative thing to do at this point? Or is it a martial art for people who can't admit they are practicing ways of hurting and killing people? (I know there are aikidoists who make no bones about that, and I respect their position, but its not something I want to do). I am getting no younger and don't want to waste time and damage my joints for no purpose."
seems like you're making a '2-sides-only' assumption that may not be accurate of fair. i think aikido can be many things for many different people--of course based on how and with whom they train.
i personally see aikido as a moving meditation for myself: in sitting meditation, one sits, closes eyes, and concentrates on observation of breath in order to quite/clear the mind. it is a bridging of mind and body, with the understanding that this bridging of mind/body creates an optimal state for a being that exists as both mind and body. the quite mind results in a calmness and a focus that creates many benefits for a person in actual life. In moving meditation (aikido) one still works on bridging the mind and body to get the same stated benefits, the only difference is that it's done while moving and with the eyes open; and, it has the additional benefit of providing all of this in the context of physical/(spiritual) relationship to another person.
For me, this can be derived from training in Aikido without even once worrying about whether i can defend against the hooligan outside, or whether im teaching myself to be a controlling/dominating person (i most assuredly am not).
it is hard to "live in the moment" in general.
i suggest that "living in the moment" while on the mat is of utmost importance, and that your question appears to be from someone who is having trouble with doing just that.
my dos pesos..