"But I know enough to say that what is good or bad, is arbitrary."

Whaaa? We're talking about a specific group of people in an organisation who want to meet specific objectives - "good" and "bad" is _not_ arbitrary here. "That's bad" means "that's not going to achieve the stated objectives and may work against them". As Becky has pointed out, classifying fandom as primarily female interferes with their stated objectives - hence, "bad".