And the excuse is always, "Well that's the joke." But a joke needs to come from the established personalities of the characters. It was completely out of character for Piggy to flee in fear when Constantine yells at her. This is Miss Piggy we're talking about--she makes Kermit run screaming from the room, lol.
In GMC, when Nicky Holiday made Piggy uncomfortable, she tried to reason with him to stop, she tried to keep some control over the situation. Plus, it made sense she's be intimidated because he's a much larger guy. It made zero sense for her to be remotely intimidated by a Kermit-sized Constantine, lol.
But I'm going to go out of a limb here and say, in the age of Twilight, Girl Power is no longer cool.