The argument that the race of Helen doesn’t matter because it’s a story is disingenuous. Regardless of how you spin it, Greece is part of Europe and its native people are considered white. I know this is weird, but white comes in many shades, including darker Italians and Greeks.
Quit acting like it’s ridiculous to assume the characters in a Greek story are “white” and not Sub-Saharan Africans.
Especially when the very same people who see no big deal in the casting are the first ones to cry white washing if a white actor plays a character they say is a POC.
Either the race matters when casting an actor or it doesn’t.