I don’t see anything savage about this. These are athletes. They compete.
Remember this was when Wes Welker was the Patriots main receiver, Welker had just come from a Pro Bowl appearance, a 2 x Second Team All-Pro and in 2007 led the league in receptions. For a HC to talk to a star player like that is savage, especially mic'd up. No coach in the league would have the balls to say something like that publicly, but I think like Gregg Popovich Bill's philosophy is he treats players equally (positively or negatively).
Watching that clip I also think it speaks to how Robert Kraft runs his organisation, that Bilichick has complete team autonomy because most sports team owners would have received a call from the star players agent saying either trade my client or get rid of the coach but Bill can operate his team the way he believe best suits winning without fear of meddling or being sacked.