I think you should talk to him about his reaction and how it makes you feel.

Since survivors of childhood SA tend to minimize, I would have thought most therapists would counter that. When I disclosed my CSA, my T immediately shifted gears. I could almost see him throwing out his original treatment plan as we talked. Several times I've said things like "it wasn't that bad" and his response is always something along the line of "if you knew a 13 year old child (the age I was at the time of my SA) was being subjected to that, would you think it was bad?" It helps me face what I experienced and not to minimize. I think if I got any kind of minimizing from him, I'd shut down about it, which would definitely not be helpful for me.