A smidge. There were/are chemicals in the water that cause the frogs to change sex, as it's one of their biological safety nets where the male frogs can become females and carry eggs if there are no females around. However, if the frogs literally transform into females, I don't think that makes them gay.

Does raise a bunch of other questions, though:

Can animals with such low intelligence who are almost totally controlled by pure instinct ever be said to have a sexual preference? Seals sometimes fuck penguins, and penguins will happily pound the shit out of dead penguins... Are they penguiniosexuals and necrophilies, or are they just so stupid that they are unable to really tell what to bone and just mount anything that partially resembles something they can screw? Even if a seal only had sex with penguins, are we able to say that this gives the seal a sexual preference, like a homosexual, or is it more that the seal found it can satisfy its mating urge with penguins and they weren't able to stop him, making it easier to hump a flightless bird than to impress a female seal and fight off the other males? It might be less a preference and more a simple case of finding an easier solution without understanding what it entails.

Same with a frog turning into a female frog. It happens because of instinct and chemical reaction. Is it likely that the frog is sitting there just craving frog sperm and the process of releasing eggs so much that it can't help but transform to live it's "Real life"? Or is it staring blankly, thinking about basically nothing at all, reacting only to outside stimuli when suddenly the levels of X in the water cause it to react by becoming female and it has no greater thought or understanding about the process? It simply is and doesn't really know any better, nor does the male frog consider the fact that this frog before it used to be male and has transformed due to a biological process. It just knows it's time to release sperm and this female frog is croaking the right croak.

... There are, in fact, toads that croak a mating call specifically to help other male toads know not to mount'em like a $2 whore, because those toads will pour their baby gravy over pretty much anything that sits still in mating season. It might be a bit generous to call them "Pansexual", as that kind of suggests they have any kind of ability to understand what they are bukkake'ing, as opposed to the much more likely scenario in which they are just on a hair-dick trigger for evolutionary purposes and will jizz on a stick of butter if it's left out of the fridge, rather than being attracted to everything they see.

So, what I'm saying is, the real question becomes: Why haven't I seen any frogs at any Pride events?? When will the oppression of frogs end? Allow frog marriage now!!