So what?


He knows you're bi and maybe other people know you're bi.. and maybe he just doesn't want anyone else jumping to conclusions about your relationship.

OR
maybe this is his understated way to let you know that his being cool with your being bi should not be taken as his being cool with you doing something about it with him....
Because, honestly, why did you tell him you were bi?

In my experience, a man telling me he is bi is preparatory to him expressing an interest.

Cut your friend some slack...
After this kind of revelation, it will take some time for him to believe that you are not gonna hit on him... that things between you are not gonna get 'weird'.

Acting all huffy over it is not gonna make you look like you are cool with his discomfort....


Far better to just joke about it....