I have to say I found this article insightful: https://medium.com/@ovenplayer/does-proton-really-support-trump-a-deeper-analysis-and-surprising-findings-aed4fee4305e
It inclines me to give him the benefit of the doubt. He clearly got stuck trying to make his point and at some point just stopped explaining. My feeling was that that was good decision because he stopped digging a deeper hole.
Don't wait around for secure clients to actually connect with WhatsApp. Platforms (like WhatsApp) need to provide integration (API) but there are no privacy or security requirements whatsoever.
Signal already indicated that they weren't planning on connecting seeing that that would offer WhatsApp access to all metadata of each message sent through that API. That's a no-go for securea apps.