No, not "always", but yes some people do have an agenda. Take James Duff for example. He flat out stated it was his goal in life to insert a LGBT character in every show he writes for. If that's not an agenda, what do you call it? And then he proceeded to start his campaign by creating one of the most unlikable character on cable TV (Rusty in Major Crimes). Other writers have said they feel pressured to include such characters or risk having their works rejected. As I said, I really don't care one way or the other, but again to consider the setting of 200+ years in the future, just how are they going to handle the plot lines? Given the current trends and track record, I expect it will be heavy-handed. Maybe I'll be pleasantly surprised.