What is the most reasonable response to a stranger saying something racist?

I was at the grocery store, picking out spatulas at the cooking utensil rack of terror. I’m a woman of color, and there was a black man about 12-15 feet away, who for reasons I do no know, I immediately thought was a threat. I looked at him, and he looked away. I stepped closer, he looked away again. Then he took a spatula off the rack and went to the other side of the aisle, where the lighter colored man (me) would not be able to see him. This led me to believe he didn’t really look threatening, so I turned around and looked at the other cooking utensils. This was probably the most threatening thing I did. About 2 minutes later, he approached me. I panicked, and stuttered out “are you about to attack me” or something like that. I don’t remember. He said “no” and continued to approach. I don’t know if I’m being paranoid, but I saw him glance at his left pocket, which my mom told me is where people carry knives. At this point I’m sure he’s going to stab me, so I slowly back away, reaching for the pepper spray in my left pocket. As I’m reaching, he gets closer, and I see that he’s not carrying anything, and he’s trying to say something, and it becomes obvious he’s visibly distraught. He said “people like you make me sick” (???) and “you thought I was a criminal” (I was trying to say something but he was interrupting) “You people want equality, but you still act like we’re second class citizens. I’m trying to show you I’m not a threat. I’m a victim too, you understand? I’m a victim too.” He stopped, muttered a little, and left. This has visibly shaken me, obviously. I can’t stop thinking about this, and I’m sure my irrational fear of black people has been strengthened, which is the last thing I need. Looking back I should have tried to talk to him more, but I didn’t realize he was trying to make a point until after he left. I’m sure there was something I should have done, but I’m not sure what. How would you respond in this situation?