I know it isn't a Justice League book but it still very much counts as a crossover.
And it isn't just Diana getting the crap beaten out of her by Mongul. It's the lecherous comments from Jason and Bruce, the lack of any meaningful exploration of her character (we see Bruce's desire to save his parents) and even Jason gets to contribute something by putting the Black Mercy on Mongul. Superman also fairs far better against Mongul than she does as he as at least able to hurt him. Even her gift ends up being pointless since it's just a replica of Kandor that Superman doesn't actually need because he has one already. All of this combined makes her presence in the story is superfluous at best, outright offensive at worst.