Since my daughter keeps watching this episode, I've had a few more thoughts on it.
First, it is a really cute, nice touch the way that Babs twists her tail around to cover up her blank flank. However, I really don't feel like knowing she was bullied a lot in Manehattan excuses her behavior throughout the episode. Regardless of whether she's been bullied in the past, Babs was horrible to the Cutie Mark Crusaders, and -- up until the prank at the end -- they were nothing but nice to her. It would be one thing if Babs had just gone along with Diamond Tiara and Silver Spoon's meanness, but she really added her own. So, I mean, it's really generous of the Cutie Mark Crusader's to instantly forgive her when they hear her back story, but I also think it's kind of naive. At best, Babs is really weak. More likely, based on her behavior, she really does have a significant mean streak of her own.