Answer: He would avoid it because of sexual diversity.
Explanation: Sexual orientation is a complicated topic, there are lots of different sexual diversities. In this case he would avoid that question because it might offend someone who identifies themselve as queer, asexual, non-binery, transexual, etc. He may be asking 'what is your sexual orientation?' to avoid leaving behind some identities of the sexual spectrum.
That statement is true.
Discussing performance is aimed to evaluate the things that the organization has done in the past.
Discussing development on the other hand is to evaluate the things that the organization should do in the future.