A couple thoughts about this.
One, she had a lot of support from people who watched this edit. It wasn’t as though she was nearing the brunt of a Rinna, Teddi, Dorit, or even Camille-sized negative social media response to her behavior. She doesn’t have cause to be that embarrassed, at least from a public-image perspective, because—like it or not—this made people come out and cheer her up, and on, not shame her into quitting.
Two, as I’m sure you’re aware, grief—and especially grief over the sudden loss of a loved one—can really throw off your decision-making process. Perhaps she stayed on the show because of both the contract issue, and the hope that it still might offer some form of “normalcy” in a life that had been thrown upside down. I’d wager that she was also stunned that this whole thing had gone down the way it does. To have a friend stab you in the back AND have people poking at you AFTER your brother dies so suddenly—while you’re also trying to run businesses... it doesn’t seem like a recipe for normal rational decisions. Staying or going from the show was one thing she had control over, and so she kept it.
Three, it wasn’t “one unpleasant day.” She’d already had enough unpleasantness, and given the unpleasantness enough time. I have to wonder if she also knew that her mother was sick—maybe not dying—but sick.