I've always wondered if it's because you think we are angry or blaming you for past or present problems. Now I cant speak for all of us but normally when either topic is brought up, it's typically about awareness. We want you to understand how this effects us emotionally and mentally, not feel targeted or ashamed.
I never want anyone to feel bad about it, even those who have stereotyped or been racist towards me! I want things to get better, not have you have hard feeling toward the conversation. Your anger and or dismissal of our feelings only hardens our hearts toward you and that does nothing to change our futures.