Several years ago, Mike Hoffman, who was playing for the Senators at the time, received a suspension without pay for two games on December 14th. This suspension was due to his cross-check on Logan Couture's helmet.
Recently, in a game between Boston and Montreal, A.J. Greer intentionally cross-checked Hoffman in the face, resulting in a one-game suspension from the Department of Player Safety.
Given that Hoffman received a two-game suspension for his offence, it is understandable that he would be upset with Greer's one-game suspension for a play that could be considered even more dangerous.