We seem to be largely talking past each other.

I agree with you that there are situations where suppressing emotions is a useful way of achieving some other goal, and that choosing to suppress emotions in those situations doesn't require believing that there's anything wrong with expressing strong emotions, and that choosing to suppress emotions in those situations without such a belief doesn't require any particular moral belief.

I agree with you that the belief that expressing strong emotions is wrong has disadvantages.

I agree with you that many people have confused beliefs about morality.

I agree with you that much suffering has been caused by moral beliefs, some more so than others.