WX-78 wasn't specifically written as a non-binary character originally. The early concept for WX was "Are they a boy trapped in a robot body or are they a robot that thinks they are a boy trapped in a robot body?" and it was left open ended for fun.
...But if it either is or if it simply thinks it's a boy then wouldn't referring to it as "he" be the polite thing? This literally makes no sense. The character's defining trait is that it claims to be male. That's as far from "non-binary" as you can possibly get.
...But if it either is or if it simply thinks it's a boy then wouldn't referring to it as "he" be the polite thing? This literally makes no sense. The character's defining trait is that it claims to be male. That's as far from "non-binary" as you can possibly get.