First of all your question is terse and I think you need to expand a bit more so we can understand exactly what you want to know. For example are there any of the very few examples in this thread that you do not agree with? As always when this is discussed people get into the "holier than thou" argument some thing like: "they are not for diversity because they do not think my aspects are important enough". Feel free to use them as good examples of why diversity is needed.
I think you can find at least four arguments for diversity by reading the negative comments in this thread.