It would have been one thing if Harper had come into the league acting like his reputation would imply. But he has been a model first year player: respectful, hard working, not a prima donna, and, by all accounts, a great teammate. The kind of player the league should want. Intentionally hitting him was completely uncalled for, and, as you said, classless.
Hamel sent a message alright. He sent a message that Hamel is stupid (by admitting what he did), a chicken*** (as Rizzo called him), and has no understanding of what old school baseball was about. Harper’s response was classic — stealing home plate on a pickoff attempt at first. Later getting a double to shortstop(!!) was just icing on the cake.
Especially in the National League where he has to bat.