> In-app ads are a significant change from WhatsApp’s original philosophy. Jan Koum and Brian Acton, who founded WhatsApp in 2009, were committed to building a simple and quick way for friends and family to communicate with end-to-end encryption
End-to-end encryption was added by Meta, they reused (part of) the Signal app code for this.
This was a big topic for years, I am surprised by this oversight.
Fun fact: For the first few years WhatsApp didn't have any encryption whatsoever. It took public pressure for them to even add TLS.
A massive oversight on the authors part and completely missing the point of early WhatsApp as first status update application and then SMS replacement.