"Wendy is sometimes interpreted as genderfluid due to her male "Wendyl" persona in "The Cissy." While it's implied to be a ruse to get into Cartman to share his trans-only bathroom and Wendy goes back to her old self in the following episodes, her casual attitude toward crossdressing, especially compared to Cartman's false "Erica" persona, made many fans assume Wendy might really want to transition."
She fucking wore jeans and a plain white t-shirt! By that logic, I must be a troon too! And it wasn't "implied" to be a ruse, it WAS a ruse!