"And, of course, some SF is set close enough to here and now that Anglo and European do apply. Since many of the writers come from those backgrounds, so does much of the fiction"

This quote by Stanley Schmidt is describing the reality that numerous sci-fi (SF) stories are set in a world that is close to our own, and the writers of these stories frequently come from Anglo and European backgrounds. This implies that the characters and settings in these stories are frequently based upon the experiences of the writers, and the cultures they come from. This can be seen in the way that the characters and settings in these stories frequently reflect the values and beliefs of Anglo and European cultures. This quote is likewise suggesting that the stories composed by these writers are frequently more relatable to readers from these backgrounds, as they can more quickly identify with the characters and settings.