Graham, I don't see how your understanding relates to historical facts?
And as someone who in all those years never was taught aikido as spiritual art I simply don't get your point. Loving peace and harmony, or, to use Brians word, being compassionate to me is not the same as spiritual. And, above all, is not unique to aikido.
IMO, I see Aikido as just another offshoot of DR - the various organizations under the Aikido and DR umbrellas all have the same roots.
Yes, this is what I think: Just different members of the familiy. Different characters, different biographies. But relatives.