So..she tried to end their rally game on purpose? Is that because Ayano was an obsessed little monster? Sounds like Uchika was battling between wanting her daughter to emulate her and not wanting her to be an obsessed monster. She could have always just changed the rules on Ayano and said "we only play badminton for x hours a day" the rest of the day we focus on other tasks.
Seems like Ayano became obsessed, but Uchika only fed that obsession. Where was Ayano's dad during all of this? Where was he when Uchika thought Ayano was too obsessed, where was he when Uchika decided to abandon both of them? Why did Uchika talk to his parents, but not him? Seems like her friend Akime should be talking to Ayano and Uchika too.