The article links to the technical white paper[0] which explains why your points are invalid.
> I'm still inclined to trust apple's iMessage a bit more
Do you have any proof why iMessage is more secure or is that statement also baseless?
[0]: https://www.whatsapp.com/security/WhatsApp-Security-Whitepap...
It states that:
- The private keys remain on the devices (which is good, but they don't need them to read your messages)
- The messages can't be read by WhatsApp (they don't say anything about their parent company Facebook or governments though).
If you read all the whitepapers and alert messages, you can totally read them in a way that allows Facebook to see, store and analyze the clear-text of every message you're sending, without anybody lying anywhere.