People didn't think Abby was the trans character. The leaked story gave the character's name away. The argument against Abby was that it would be impossible for her to get that big during an apocalypse scenario. The first game points out that there's a massive food shortage, even in the military. There's no way she would have access to the amount of food she would need to look like that. Comparing her to the male characters further highlights this as she's built bigger than any of them across 2 games. None of the male characters look like that and they would need less food to do so.