Not that Shannen was necessarily a saint (https://www.lipstickalley.com/threads/lifetimes-the-unauthorized-beverly-hills-90210-story.931820/page-7#post-23665031) but it isn't like Jennie Garth was a picnic to work with either. Jennie allegedly had issues (https://forums.primetimer.com/topic/57118-again-with-this-mini-monna-dartin-draguates/?do=findComment&comment=3251259) with Tiffani Amber Thiessen when she first came on. Emma Caufield said she didn't get along (https://forums.primetimer.com/topic/57118-again-with-this-mini-monna-dartin-draguates/?do=findComment&comment=3253840) with "the girls" on the show because they were very catty but made sure to point out it wasn't Tori Spelling. Bare in mind that Shannen was long gone by that point. And there were rumors that Jennie didn't get along with Hilary Swank (https://www.tvguide.com/news/hilary-swank-scarred-13148/) (and possibly Vanessa Marcil (https://forums.primetimer.com/topic/57118-again-with-this-mini-monna-dartin-draguates/?do=findComment&comment=3260349)), and Jessica Alba said she wasn't allowed (http://www.gossiprocks.com/forum/gossip-archive/39992-jessica-alba-banned-making-eye-contact-beverly-hills-90210-stars.html) to look at any of the 90210 actors in the eye when not filming.

If Jennie Garth was so mean to other actresses on the show, how come nobody ever called her out on the behavior at the time? Shannen was the one who got branded a b**ch, but since the show Tiffani and others have spoken about the mean girl culture on set.