Then if yarijutsu in disguise is not what we're doing, there is no need to distinguish between the ends of the jo in aikijo by means such as coloring them distinctive colors. That was the point that I made several times both before and since this yarijutsu digression.
I think you're drawing a false dichotomy here. You are assuming that aikijo must either be (a) just spearfighting with a stick in place of the spear or (b) a staff art which has nothing to do with spear and which therefore cannot be usefully informed by spear thinking. Why can't it be (c) a staff art heavily influenced by its founder's study of the spear, the understanding of which might therefore occasionally be aided by spear visualization?