Grier was given the GM title in 2016, but wasn't the head of football operations until 2019. That means that from 2016 until 2019 he wasn't implementing his philosophies. During that time he was implementing Tannenbaum's philosophies. Tannenbaum was in charge of football operations and the GM was under him. In some organizations the GM has full authority but back then, that wasn't how Miami's FO was structured. They've simplified it since and now (since 2019) Grier still has the GM title, but he has full control of football operations. I think some fans get confused by that and blame Grier for things they didn't like when Tannenbaum was in charge of football operations.