As for the whistleblower, I'm very skeptical of her — to be a tech PM against encryption, and somehow linking e2e encryption to making the platform less safe, is dubious at best. Removing misinformation and calls to violence on the Facebook platform doesn't need to include monitoring private messages.
The idea that she's been a PM at large tech companies for 15 years and doesn't understand that Facebook monitoring messages will mean China can monitor those messages is almost too suspicious to believe.