What Happens When My Staff Don't Want to Talk to Me?

I pride myself on making sure that I have an inclusive team. And while I thought I was doing a lot of good in initiating and having those conversations what has ended up happening is that my staff are having the conversations with me but they're not willing to have the conversations with my boss. My boss doesn't says things on occasion unintentionally that are microaggressions or otherwise make my staff feel very uncomfortable. So when he does it to my staff instead of feeling like I do which is the sense of I'm not your administrative assistant I am the leader of this organization. Their feeling is I’m not your slave. You hired me to do a job in this organization and that job