What do you think happens when a mouse finds a large carcass in the wild? They just take a few nibbles and then go "that's enough, time for some greens now. Gotta keep my diet balanced". No, they gorge themselves on the opportunistic meal and will return each night until it's gone or inedibly rotten.

The study is fine. The conclusions, interesting. The sudden 'mouse diet & gut-study experts' disagreeing because they don't like it, reminds me of Facebook tbh.