Backbiting Or Criticism Behind Back?
The etiquettes in this case are to separate the idea/action from the person and discuss those ideas/actions independently . If they are being crticized with respect to a specific person and solely involve his criticism behind his back, then this would tantamount to Backbiting and shoule be avoided. This however does not apply to public figures like religious scholars and Politicians, but still those discussions should be free from any useless speculation or character assassination. Following discussion is a good start to understand important aspects regarding Backbiting: https://ghamidi.com/audios/backbiting-how-to-prevent-it-861