Gadot confirms that the emotional side of 
WW 's ending deliberately doesn't sync up with Diana's character in 
BvS: DoJ at all (
io9):
"None of us knew exactly, 
exactly, the back story of 
Wonder Woman. And once they decided to shoot the solo movie for Wonder Woman and we started to dig in to understand the core of this character, we realized that, actually, there is no way that Wonder Woman would ever give up on mankind.
The reason why she left the island was because she wanted to make their lives better and safer—they are her calling. So, I’m giving you a very honest answer, but it was—sometimes in a creative process, 
you establish something that is not necessarily the right decision, but then you can always correct it and change it."
So, folks, there you have it. All those saying that 
WW adhered to Snyder's grand plan, and that 
BvS and 
WW don't totally contradict each other in this respect, are objectively mistaken. The 
WW team didn't like the "Diana turned her back on humanity for a century" bit from 
BvS, so they straight-up ignored it. Period.