Ah, classic Mario. After this incident he went on a tirade to the press and called the NHL a glorified minor league and threatened to retire - same crap he always pulled when he got mad, even as an owner during the Islanders incident.
Along with Richter's 70-foot goal allowed to Ron Francis in the same series, this incident became another legendary part of the 54-year curse. As has been said, the play itself was common for the era. Chopping a guy on the gloves - sometimes repeatedly- was an accepted defensive play. Sometimes you missed and hit a guy's wrist, and a slashing penalty may or may not have been called. NHL playoff series back then were also total wars of attrition. It was accepted that you wore down the other side through any means possible and you had to absolutely kill someone for a penalty to be called. What are called "late hits" today were known as "finishing your checks" back then and were one of the marks of a good player. Slewfoots were a good way to win a board battle. Dirty stickwork behind the play was common (only one ref, so if his back was turned to you then all bets were off). By the time two teams got to the finals, they were both made up of walking hospital beds.
Objectivity on this matter is also affected because Mario and the Pens of the 90's had much the same perception as Crosby and the Pens have today: a privileged organization led by a whining Prima donna who does not want to play by the same rules as the rest of us. Many here might be too young to remember, but for much of Mario's career he was a complete brat. He refused to even go on stage when the Pens drafted him, he chain smoked, had to be forced to exercise, was lazy in practice, constantly chirped the refs, repeatedly criticized the NHL in the papers, and on top of all that he was being force-fed down everyone's throat as the greatest thing to happen to hockey since the Zamboni was invented.
One of my favorite Lemieux moments was when he burst out of the penalty box with the intention of attacking Kerry Fraser over a two-minute minor for butt-ending a guy in the face. Did he get suspended? Nope. He was fined $500 and told not to do it again. He then went off in the papers saying he was fed up with the league and would no longer promote it. The funny thing is, Mario's constant tantrums and complaints directly led to the discussions that ushered in the changes you see in the NHL today.