First: I agree with all of your practical advice. I'm making a meta point to security people like you and the author of the linked post.

And I'm not sure it's "helpful" really . It's more musing on whether or not this kind of advice is hurting more than helping. What you are saying amounts to "Crypto is really hard so use expert-authored solutions." But in my experience what people hear is "Crypto is Hugely Important and I'm using a expert-authored solution and using the same jargon, so you need to listen to me about all that security stuff and do what I say even though it's totally impractical."

Broadly, I guess I'm thinking that this creates little BOfH monsters, where a more nuanced, "big picture" frame might engender more thought about costs and tradeoffs.