Sticks and stones. They're just words (and in this case, words typed over a computer). It's not like she was in his face screaming at him. Did Yormark feel threatened by her words? I doubt it. Could/should he have chosen to take the high road and ignore all of the tweets coming from Devils fans, including LA? Definitely. Should he have expected the barrage of tweets that was to follow after his BS comments about the rats? Absolutely.
If he was my employee, I'd be awfully pissed with his behavior. She's just a fan. But he is a representative/face of a professional organization. Big difference.
Many fans call out team executives for being too distant with fans and being too professional. Take Lou for example. We go after him for being a little too professional on here all the time. Fans are always asking for team ownership/management to be more interactive with fans, but then throw a hissy fit when they try in this case.
They should be held to a certain standard, but not held against a double-standard by fans.