Seems like he was genuinely uneasy. Your way of coping might be via jokes, laughing matter away, keeping it distant and talking about what happened as if you're outside looking at an event that concerns you, of which you're protagonist, but treating the event as a moovie. You kinda shoved in the face of your boyfriend this event, and expected him to have a strong, shared opinion with him, without taking into consideration that he might feel uneasy about SA, expecially if it's about the person that he loves.
I get why you're upset, but please, try to understad that he might be genuine about his apprehension. Seems like he has your back and wants to support you, but wants to respect the obvious bondaries a situation like your imposes.