Hoffman recently posted an Instagram story, stating that he was given a 2 game suspension for his hit against Logan Couture back in 2016, but that Greer was only given a one game suspension for intentionally cross-checking Hoffman in the face. Hoffman made sure to show off the scab on his chin, which was cut open as a result of the cross-check.
It makes sense that Hoffman is upset about the length of Greer's suspension, if Hoffman got 2 games back in 2016, why shouldn't Greer get 2 games for an arguably more dangerous play.