Forced Diversity is when the "Diverse feature" of the character becomes the main point. For example Ana Bray is gay and they pretty much shove it down your throat. On the opposite end Tracer in Overwatch is also gay yet any comic only points out a part of that and isnt the main point of it. If you watch the video he states that Forced Diversity is Diversity inserted into the medium for the sake of being Diverse.