And what do people expect her manager to do? "Hey Brittany, if you don't close these deals, you would be underperforming and we're going to do layoffs soon." That would make her perform even worse and stress her out. Her manager probably didn't even know layoffs were happening until a few days before, so there wouldn't be any time for a PIP.
Honestly, sounds like Cloudflare dodged a bullet. This girl seems like a nightmare to have work for your company. Recording a private company conversation for the internet, unable to take responsibility for her own failures in not closing her deals, outing all her work friends and using them as examples to defend her situation - she was seriously a liability.
There's nothing wrong with defending yourself from unfair work practices, but this was every bit fair for Cloudflare. Take a stance against work sexism, unfair compensation, unfair working conditions, hazing, etc, but this isn't one of those cases.