"Song Jiawen, come along too," Xue Weisong finally turned to face Song Jiawen after agreeing with everyone else and gently persuaded, "I know you're the only girl from our class going, and it might be a bit uncomfortable, but there are already so few girls in our class. You can't just skip out on every activity because of this, right? College life has only just begun."
Having a meal together is a normal class activity.
Xue Weisong was also smart not to bring up Xia Shi. The celebration was for Shen Mengfei's election win; as the other candidate, if she had graciously conceded, it would have been fine. However, she acted as though she was aggrieved, as though everyone had bullied her.
How could they invite her to join them?
And as for not celebrating out of consideration for Xia Shi's feelings... would everyone else be willing?