I think that the "universal peace and love" idea might have just been O Sensei's personal take on the Aikido koan.
If I understand correctly, a koan can't be answered but it's value is in it's ability to stimilute a train of thought concerning the fundamental nature of things. To frame Aikido as a koan take the physical techniques and objectives of Aikido; that is, redirecting energy, natural flowing movement and minimizing harm to your opponent. Start by trying to understand how these things inter-relate and why these objectives are in harmony with each other. Ask yourself how these ideas alter your impact on the world around you. It's easy to believe that if you spend a life time meditating on the Aikido koan that you might arrive at the belief that budo is love.
Here's something I've been thinking of. Consider how conflict is resolved using common American philosophy (Hollywood action films.) American philosophy is based on the idea that along with great power comes the responsiblity to be righteous in your actions. Furhter more, the righteous should not INSTIGATE agression. The righteous should instead respond to agression by using their superior power to pound the evil doer into submission. Examples: Steven Seagal uses Aikido to grind punks into the dirt.
But agression is nothing more than a natural reaction to fear. So what happens if you have enough confidence in your martial arts skills that you don't feel fear when confronted by a threat? In many martial arts and in American philosophy, you use your superior skill to put some hurt on the person threatening you because it is righteous to do so. In Aikido philosophy, you use your absence of fear as your basis of power to attempt a means of resolving the conflict without harm. This would, almost certainly, rarely involve violence. In the absence of fear and with the intent to resolve conflict without harm...what's left? Is it love?
These are my half-formed thoughts on the matter. Please feel free to criticize.