Regé-Jean Page seems to be reacting to a wide-ranging interview with Ray Fisher in The Hollywood Reporter that looked into questionable practices across the board at Warner Bros, and specifically on the set of the Justice League. Fisher famously accused director Joss Whedon of abusive behavior, but after a Warner investigation, the studio determined there wasn’t anything to it.
Fisher’s interview in THR included several other anecdotes and examples of what he claims is a far from inclusive environment at Warner, including one in which he threatened to derail Gal Gadot's career if she continued to push back on the set of the Justice League. Another incident was when Page was up for a role as Superman’s father in Syfy‘s Krypton, which he lost out to because he isn’t white.
Cochairman of DC Films Geoff Johns said at the time that Superman “could not have a Black grandfather,” according to THR. Johns also vetoed adding a gay character.