Solid advice. I think some of the onus is on the reader too, not just the writer, but I think you’re saying something that really needs to be said.
I remember how this was the standard in grad school. Everything you wrote had to be backed, proven or disproven. Pretty much like when you said (paraphrasing) writers should take time to try and disprove their own opinions.
That’s really great advice.
I also think that analysis on the reader’s side can be as easy as asking yourself why you believe whatever it is you believe. What is it about the article that resonates exactly and why. Keep digging. That’s analysis too.