With everything that the Keating Five have been through on How To Get Away With Murder regarding Annalise up until this point, it's a wonder that it's taken them this long to tell her like it is. So when the Keating Five attacked Annalise on How To Get Away With Murder, it was a long time coming and totally justified. They pretty much laid into their professor and mentor, and everything they gave to her she took willingly. Probably because even she knew how right they were.
From the very first season, when Annalise helped the Keating Five cover up Sam's murder, they were in it with her. Then again, she helped them when she really didn't have to, so while she's done her fair share of murder cover-ups, the Keating Five aren't exactly close to being innocent either. It was almost like, when they were basically roasting Annalise, they were children telling off their mother and complaining about all the reasons their lives are unfair. There's a reason why Thursday's episode of How To Get Away With Murder was called "Call It Mother's Intuition" and it's not just because of the case they took on, which involved some serious mommy issues all on its own.
Viewers can all agree that with all of the shenanigans the Keating Five have pulled, Annalise has been their matriarch, there to bail them out and cover up what they did. So when they came at her, it was justified, but also a slight case of the pot calling the kettle black.
Take, for example, when Asher killed Emily Sinclair and Annalise and her team were there to clean up his mess. And it's a process that has been repeated time and time again. Maybe none of the Keating Five would've ever committed such heinous crimes if she'd never taken them under her wing. However, they are also all adults who are capable of making their own decisions. When the Keating Five came at Annalise in an impromptu roast, they were finally able to tell her all of the ways she'd made them feel small or insignificant and how she's negatively impacted their lives. And they weren't wrong in any way, but at this point, they're all in this together.
There is very little "good" on How To Get Away With Murder anymore and that includes the Keating Five. For better or for worse, everyone in this group has blood on their hands at this point.