I see a different reason Romulans are so upset. The Romulans and Vulcans were one people at one point with the major split being the Vulcans embracing logic and rejecting the hot-blooded and passionate Romulans. So millennia later do the Vulcans soften and embrace their emotion-having brothers? No. They find these other hot-blooded and passionate creatures called humans and then work patiently to shepherd them and their “Federation of Planets” into dominance in the Alpha quadrant of the galaxy all while still keeping Romulans at arms length. That would leave me bitter too.