I myself look equally at art. Firstly though I do not see Aikido as fighting so the above doesn't apply. I do not see Aikido as self defence either as I see it as a 'selfless' pursuit. To handle the attacker without thought of self and therefor no self defence. The martial is indeed the how. Art does not imply purpose to me and therefor has nothing to do with the why. Why is only and always be solely to do with your purpose. The purpose of the art of aikido in my opinion is harmony. To reach a competency level of 'artist' is another matter.
You see it as selfless - why does it also have to have a purpose?