This is not really a spoiler since you already know the entire movie, even if you've never heard of it and didn't see the first one. It annoyed my girlfriend when I tried to address them with her so I am instead engaging you kvetchers on ListApp.
  1. The auditions ban
    The whole conflict is centered around the group being dealt a punishment that prevents them from recruiting new members. But at the same time, every girl in the group is a senior so they haven't been holding auditions for the last 3 years. This is stupid.
  2. The group's member sustainability
    All of the girls are seniors . The one "legacy" girl who gets in as a freshman also gets in with a producer who will presumably make her famous and take her on a tour that necessitates dropping out of school/the Bellas singing group. So, we are left to conclude that the 2015-16 school year won't see any members in the group. Who is there to conduct auditions if everyone else has graduated or otherwise moved on with their lives? No current group = no future group = this is stupid.
  3. The main character's boyfriend
    Homeboy has maybe 6 lines of dialogue. The entire movie. How does the main character's love interest - in a romantic comedy - from the first movie become totally inconsequential in the sequel? She doesn't call him, text him, ask for his thoughts about any of her many problems, fight with him, sleep with him or do anything else to make us believe their love was something we should have cared about in the first movie because she clearly doesn't care. This is stupid.
  4. The microphones
    During the Acan'tcareanylessabouthis World Championships, the Bellas start out wearing head gear microphones. At the end of the performance, they have mics in their hands and no expensive equipments on their beautiful faces. This is not stupid but it speaks to the utter disregard for consistency throughout the entire production and THAT is stupid.