The play was dirty and does necessitate a suspension, however six games seems a little too severe. Especially when suspensions are supposed to take into account player history, Perron has played over 1100 NHL games without a suspension. To Perron and his agent, and many NHL fans, giving him a six-game suspension for that play given his history is way too harsh. Looking at similar suspensions as well, others have been suspended for less games for the same play.
The NHLPA and David Perron have already appealed the suspension to commissioner Gary Bettman, who upheld the decision from the Department of Player Safety. Now, they will be heard by the independent arbitrator, who has a record of reducing suspensions even after the commissioner has upheld them. Perron has already served the suspension, so he can't get the games played back, but he will get salary returned to him.