That's just how it works. Players have a finite amount of energy. Last night's game required the team to shut down an extraordinary scorer on the other team, so it was necessary to sacrifice some offense to slow him down, and they did better than just slowing him down. One way a defensive-oriented team can improve offensively is to be more deliberate in working for higher-percentage shots. This was the entire basis of Dick Bennett's teams over several decades. One thing Shrews did last night was called "dorking." This is when a coach has his team ignore an offensive player who is outside the key and beg him to shoot, while double-teaming an opponent he doesn't want shooting or driving. Shrews did this at PSU sometimes.
I really don't like what ND does offensively most of the time, but trust me when I say that Shrews knows X's and O's. Other coaches recognize this as well, because they have to prepare to play his teams.