There's always going to be people who gatekeep sci-fi. "That story is fantasy", "the science is unrealistic," "I only read hard sci-fi..."
I take a more liberal stance on the matter: stories can have many genres, and if one of them is sci-fi then it's good enough. DCC to me is fantasy/dark comedy in a sci-fi setting, so it's perfectly cromulent for this community.
If things get too busy in the future I may advocate for splitting by subgenre for example, but in the end as long as there is a reliable enough way to filter posts I see no point in excluding contributions made in good faith.