The myth has been then patriarchally re-read via the insertion of Zeus, who disguises himself as Artemis in order to seduce Callisto (Ovid [The Metamorphoses, Book 2, vv. 401-530] says it was actually rape, but  warns against taking rape tales in Greek mythology too seriously - by the way, had Callisto been actually overpowered as Ovid claims, the wrath of Artemis and Hera would have been groundless)
This reading, put forth by a luminary of comparative religion, is apparently unassailable; but I think that I can cast some doubts at least.
First, this is an essentialist reading: it assumes that, if Zeus turns himself into a woman, this is forgery, interested interpolation, something against the logic of a myth.
Yet Zeus turned himself into a host of persons (as in the myth of Alcmene), animals (as in the myth of Europa), and things (as in the myth of Danae) to lay his women (and his men - e. g. Ganymede); he even carried Dionysus within himself (he sewed him into his thigh after unwittingly killing his mother Semele); he bore Athena after engulfing alive and whole her mother Metis (who managed to carry on her pregnancy within the body of the god who had impregnated her) - and in Greek mythology there is at least another person who changed sex (Tiresias) and another who changed gender (Achilles) - I'll talk about them later.
Thinking that Zeus can believably turn himself into anything but a woman, in my opinion, becomes more the Michigan Womyn’s Music Festival than Greek mythology.
In fact,  takes trouble to warn us that in Rome the herma of Jupiter Terminus (Jupiter is Zeus' Roman counterpart) bore the marks of both sexes, and other myths of Zeus' (like the aforementioned myth of Metis and Athena) point not just to bisexuality, but to hermaphroditism as well, and that for ancient Greeks, "power is the essence of bisexuality".
Second, a patriarchal re-reading is supposed to be oppressive, but Zeus' intervention opens up new opportunities to the protagonists, instead of foreclosing them: Zeus stops being cissexual, Callisto stops being monosexual.
Eva Cantarella in  remarks that in Archaic Greece, the one told by the Homeric Poems (which record its transition to Classical Greece) and Sappho, homosexual behavior was part of initiation to adulthood, and in Classical Greece it was heavily regulated between males in order to preserve its initiatory value; but between females, after losing its initiatory value it had in Sappho's times, became invisible at least, and, as far as we can glean, had it surfaced, it would have been held up to mockery, not deemed worthy of admiration.
According to today's criteria, the normative sexual identity for the dominant male of Classical Greece was (heavily regulated) bisexuality; for the subaltern female it was monosexuality, in the semblance of compulsory heterosexuality.
Those who advocate the patriarchal re-reading of Callisto's myth have to interpret it as marking the transition for Greek women from initiatory homosexuality to compulsory heterosexuality - and explain why the former is supposedly more feminist than the latter, as neither is chosen, but socially imposed. Perchance is a female tyrant better than a male despot?
In my opinion, Callisto (seduced, rather than raped, notwithstanding Ovid's tale) moved from monosexuals' disenfranchisement to bisexuals' power, exercised against the heteropatriarchal rules of Greek society, which in fact takes a really heavy toll on her.
By the way, Zeus loses nothing by turning himself into a woman: even if you ignore , the myths of Tiresias and Achilles show that those who can transition between sexes or genders are endowed with special gifts, according to Greek mythology.
As a matter of fact, Tiresias, who was born male, lived seven years as a woman, and then become male again, lost his eyesight because he disclosed what it was already an open secret (that women enjoy sex more than men), but he was the clairvoyant par excellence in Greek mythology; Achilles was forced to cross-dress by his mother, to prevent his being recruited for the Trojan war, but, unmasked by Ulysses, he proved to be brave beyond compare.
By turning himself into a woman in this occasion, Zeus just proves his supremacy over the Olympic Pantheon for the upteenth time - I know of no other god up to it (Hermaphroditus, who gave his/her name to the medical-biological condition, is more an apparent than a real exception, since  warns us that, even though (s)he is a god(dess) with divine genealogy, (s)he wasn't worshipped - so he is a literary-artistic character, not a religious one).
As for Greeks bisexuality and transexuality (or transgenderism, in this myth, as Zeus managed to impregnate Callisto) opened up more opportunities than cissexuality and monosexuality, why should we interpret the myth of Callisto as a defeat for the female gender?
I was taught at (Grammar) School that the main elements of Greek tragedy were:
Aeschylus wrote a lost tragedy about Callisto, so he was able to find in her access to bisexuality a prime example of hybris, which required a really heavy nemesis by the goddesses vested into heteropatriarchy:
- Artemis ejects Callisto from her retinue – Artemis had developed a homonormativity mirroring Hera's heteronormativity (in fact, in a version of the myth, Callisto is turned into a female bear by Artemis as per Hera's orders), and the prized value given to maidenhead (as in the American idiom Gold Star Lesbian) by heteronormative and homonormative women alike doesn't lead the latter to wonder whether they've made a mistake (as, on the contrary, the author of  does);
- Hera turns Callisto into a female bear;
- Callisto is put at risk of being killed by her own son Arcas - Zeus forfends that by turning Callisto into the Ursa Major and Arcas into the star Arcturus (in other versions of the myth, into the Ursa Minor);
- Hera also begs Tethys and Oceanus to prevent the stars of the Ursa Major from setting and resting (they're actually near the celestial pole) - but that makes them extremely useful for seafarers, so I doubt that it's a real detriment to them.