I'm not entirely comfortable with using "whoring" in the way that you use it in this case.
It's the most possible accurate word, actually, IMO. We've got this patron-champion relationship between Diana and Athena (and to some extent Aphrodite, Artemis et al) which is a significant commitment and emotional bond between them - in nature, it's primarily filial, but in intensity and exclusivity, it's very comparable to a marriage, particularly as we see it in Rucka's run. There is an insane amount of love and trust there, and a very definite sense of primacy and commitment.
Further, given the nature of Diana, we can feel secure in assuming this is the ideal model for a patron-champion relationship in her culture; she's the pride of the amazons, the incarnation of what they aspire to, the one who embodies their cultural mores, so it only follows that she's an ideal amazon in this way too. This is what it's supposed to look like when a god has a champion: faith, love, loyalty, devotion above and before all others, in total reciprocation. Faith in exchange for faith, love in return for love, loyalty and devotion met by loyalty and devotion.
When Diana comes to Kane Milohai, she betrays that bond with Athena, takes that faith, love, loyalty, and devotion above and before all others and gives it to some random dude as, basically, a business transaction. Faith in exchange for a magic boat, love in return for a door to Themyscira, loyalty and devotion met by... I dunno, he seems more fondly amused by her than anything. In short: She takes an expression of love that was supposed to be exclusive and reciprocal and freely given and a deep lifelong commitment, and hands it to the first stranger who was willing to pay.
Understandable? Sure (if you can overlook the Shamazons idiocy that forms half the bedrock of her motivation). There's plenty of reason to empathize with her, to the point where even Athena herself might reasonably not condemn her for it. And that's before you consider that we're looking at cultural virtues here and not objective ones (back on the other side of the metaphor, our culture values marriage over prostitution, but even within our ranks you'll find folks who disagree with the metric for both; surely there are amazons who'd consider "free agent" a better MO than the standard champion system, and we readers being outside her culture have no reason at all to share Diana's perspective). But really... that only reinforces the comparison.