Diana is not saying, “I rejected humanity and condemn them for their division.”
She’s saying, “I spared them my divinity because it doesn’t work with their division.”
Defining The Controversy
I continue to see confusion about the sequence of events and statements, so to make it explicitly clear: Diana defeats Ares, then [by her own timeline] she walks away from mankind, she fights Doomsday, and she tells Bruce she walked away, Bruce sends her the original photo, and it is then that Wonder Woman says, “So I stay, I fight, and I give for the world I know can be. This is my mission now. Forever.” Before leaping into the light in our time.
We have no explicit indication that she has been doing this between defeating Ares and defeating Doomsday other than her statement that she’s killed “things”- plural- from other “worlds”- again plural- before. So Diana’s last lines in Wonder Woman come after Dawn of Justice and are not in contradiction with BvS. Anything based on the last lines is a comprehension error and not a contradiction.
However, contradiction can still be alleged based on the explicit statement that Diana believes in love… and the general idea or attitude that she is an irrepressible activist.
Concisely, “If you love, you can’t walk away.” and/or “Heroes can’t walk away.”