We often want to point to certain characteristics of another when we are asked why we love someone. I want to suggest that the question "why do you love" is a red herring. Looking into the world of animals that do not use conceptual language in the way we do, we see care, devotion, attention and concern abound, sometimes even inter-species. No-one is asking why.
"How do I love thee, let me count the ways" begins Elizabeth Barrett Browning's sonnet. But she doesn't count why she loves, she enumerates the feelings of care she experiences. There is no search for specific cause, a reason, or attribute that deserves love. None of us can deserve love, because that would mean that there are some qualities one can possess that are worthy of love and some not. All our qualities - intelligence, beauty, youth, height, humour or sourness - can change. All are ephemeral in the end. If we are fortunate enough to be loved, it is a spontaneous event for the one who loves us, arising without a reason.
If you spend enough time with someone who doesn't speak your language - a cat, dog, mouse, moose or even a jumping spider - you begin to see their motivations, their emotions, and you slowly notice your increasing advocacy for their interests, your desire for them to succeed in their plans (that plan could be a 20 hour nap in the case of a cat). You begin to love them because you are seeing them, and you didn't plan it, and you cant' stop it, and there is no reason for it.
We can also restrain our attention, compartmentalize our empathy and ignore. These capacities often help us stay alive, for if you feel that the aims of the smallest among us are as important as yours, how then to use them as a resource for our own survival? It might mean the end of all beings with the capacity to notice their effect on the environment and with the will to attempt to stop the harm. Species survival and love - are these at odds with one another?
If you let yourself love, you may destroy yourself. This is in fact the great power hidden within what seems to be one of life's greatest personal experiences - the power to transform, and transformation is an alchemy that is irreversible. But isn't this the aim of yoga - to transcend the limited self? The degree to which we recognize the importance of all beings - the sense of centrality in their own lives they must feel, as we do - is the degree to which we might love. No amount of marching, advocacy, blame or attempts at selflessness can accomplish this internal transformation, but the spontaneous steps taken that arise from a state of true appreciation might change the world.