I think it was the best way to handle it. Why leave Snyder hanging? Let him move on to other projects rather than leave open the possibility that he'll be directing a massive blockbuster that would no doubt require him to devote years of his life to. As for his fans, it's best to rip that bandaid off quickly, otherwise people would feel like they were being strung along.
Honesty is always the best policy here. What she said was smart and well-intentioned. We're happy that Snyder got to deliver his version of Justice League to his fans, but we're moving on to a Multiverse of diverse takes on these characters that can interact or stand-alone depending upon the needs of each project.