The teachers were suspicious of Yang Xuan's words from the start, as he sounded too ridiculous.
A girl failed to get him, so she beat him up— people were going to taunt him so badly if they found out!
Especially when it was a girl as weak and delicate as Xia Xibei. How could she have fought a big boy like Yang Xuan?
Yang Xuan's mother's attitude and behavior didn't do him any favors either, repulsing the teachers even more.
As for Yang Xuan's father, although he didn't say more than a few lines, his lack of participation was exactly what roused their distaste. He was quiet, standing behind his wife and his son, allowing them to partake in this type of behavior. If it wasn't for his presence, Yang Xuan's mother wouldn't have dared to be so fierce and unreasonable.