From what I’ve seen of people using the term ‘forced diversity’ on the forums in the past, I believe they were mainly discussing pieces where having a widely diverse cast doesn’t fit to the particular time period, or location that the story is set, but they then feel the need to add in more diverse characters to make it more inclusive, even if it’s not as authentic as in reality. Not that they themselves don’t see diversity in reality, or that they are unfamiliar with it.
That’s just what I’ve seen being discussed in the past, so thought I’d offer that as a possible explanation to your question. 