もちろんバスケに対して真剣に取り組むからこそ、ではあるんだろうが。
What does ではあるんだろうが mean in this sentence?
The story was about the narrator's classmate, who was strict during the basketball practice and it seemed he (the classmate) was being hated by their underclassmen who joined the basketball club. This classmate is striving to become a professional basketball player, that's why he takes basketball seriously (as mentioned on バスケに対して真剣に取り組むからこそ).