"Why did I get put in jail and a nickelodeon star has had NO punishment(s) so far? +."
1. She Meant What She Said: Lohan was jailed following a DUI arrest; Bynes wasn't. Lohan's swipe is a simple, instinctive cry of "No fair!"
To be fair to Bynes, it's also a simplistic cry. Is Bynes not being punished, or has she just not been punished yet? Lohan wasn't jailed (the first time) until some six months had elapsed since her (first) DUI. In the interim, Lohan was arrested again for DUI. Both times, she was alleged to have been in possession of cocaine. By contrast, three months have passed now since Bynes was charged with DUI (sans any additional drug-possession allegations). And while Bynes has subsequently been charged with misdemeanor hit-and-run, that case is considered separate, i.e., it doesn't get her in any hotter water with prosecutors pursuing the DUI.
2. She's Pulling Rank. Referring to Bynes as a "nickelodeon star," a callback to the actress' All That and Amanda Show credits, feels like a slam from the olden days when movie stars looked down on TV stars (and theater actors looked down on everyone). Since Lohan's done TV herself, and Bynes has done movies, it's possible Lohan is actually pulling rank on Nickelodeon. In a followup tweet, Lohan thanked her childhood employer, Nick's rival Disney, for its support.
3. She's Been Stewing About Bynes for a Long, Long Time: Back in the mid-to-late aughts, when Lohan entered her Robert Downey Jr.-before-Iron Man phase, and she and Britney Spears and Paris Hilton were portrayed as the Bad Avengers, Bynes was held up as a model of virtuous young Hollywood. Bynes herself typically demurred when the talk turned to Lohan, but, given Lohan's tweets, it's possible Lohan thinks Bynes didn't demur hard enough.