Well, more like intimidate. If you don't include every group (gender, race, age, sexual orientation, religion, disability, etc), then it's a clear strike. How could you ignore X group? But, if you only have one example of that group, then you run the risk of a representation problem. Now that character is the sole representation of that group and everything they do unfairly reflects upon that group. This, of course happens in real life too.
What's the solution then? This is obviously an exaggeration, but it sounds like in order to construct the perfect ensemble, it's going to have to be an immense cast of multiple representations of each group. That is, our diverse cast, needs to also be, well intrinsically diverse.
That's where I get a little hung up. Good news is that I don't think that's the ultimate message here, that every book needs the perfect ensemble. At the very least we need to be conscious of the various forces at play in our in books and minds and what the overt and subvert messages are. Else we fall victim to our books being just another example of our own fallible culture.
It's another layer of thought and review when writing and editing. How does this book depict people? What messages am I sending? We can't please everyone, but at least we can avoid the pitfalls of ignoring the rich diversity of people our own world has. And if we're more inclusive in the author community, that's going to naturally produce more ideas and enrich the culture as well.
I think this continued evolution will reap a stronger and healthier field of books and that every reader, no matter where they are coming from, can find a book that they identify with and recognizes their existence, celebrates their uniqueness and ultimately embraces their humanity.