This occurred after a previous play where Evander Kane cross-checked him, making Pietrangelo feel slighted. However, he showed no remorse for his actions and went on to call the cross-check "premeditated," which seems unreasonable.
Rather than addressing the on-ice officiating, Pietrangelo directed his anger toward the lack of action taken by the Department of Player Safety.
As a result, he received a one-game suspension for his actions toward a star player, which is a reasonably light punishment considering the severity of his actions.
Overall, Pietrangelo's behavior was unacceptable, and he should have taken a more constructive approach to address his concerns.