I also think that true love has to be without any selfish motive. Which rules out pretty much all types of human love. Perhaps being a separate self rules out knowing or liveing this type of pure love.
If that is true, wouldn't it be better not to call "love" what you're speaking about? For "love" as we know it from experience requires both "being a separate self" -- or, rather, two separate selves at the very least -- and overcoming the separation.
Fwiw, the formula "impartial love" reminds me of one Talmudic passage which was nicely pointed out and commented by French (and Jewish) philosopher Emmanuel Lévinas. As it often goes, the Talmud was attempting at reconciling two formally antithetic Biblical expressions: (1) "(God) is not partial, in Hebrew lô' yissa' panim, lit. "he doesn't lift the face up" (e.g. Deuteronomy 10:17); and (2) the priestly blessing in Numbers 9:26, "the LORD lift up his face (yissa' Yhwh panayw) upon you, and give you peace." The Talmudic solution was the following: only after the judgement is passed does God "lift up the face". That was the rabbinical way of harmonising "grace", or "love", and "justice" or "impartiality". Food for thought, at least if you take it at a deep level (as Lévinas did).
The famous Gospel saying "love your enemies" is paradoxical: the first thing it implies (although most Christians overlook it) is that you do have enemies, i.e. people that don't love you and that you don't love. From that point it stretches love out of its natural boundaries. Now if you redefine love from the conclusion (such as the WT does with its silly definition of "principle-based love") you just lose both the paradox and the meaning of "love".
As for the "love which moves the stars", as Dante said (I already quoted the conclusion of the Divine Comedy in another of your threads), it can only be appreciated as a poetical, i.e. analogical statement. Imo, taking the poetical definition of a selfless love as a starting point, and from it denying human, partial "love" the right to call itself love, is the kind of "idealistic sin against life" scholastic Christianity was always guilty of, as Nietzsche pointed out.