The first point on your list is something that I come back fairly frequently when reading through blog posts like this, or (for example) listening to things like TED talks. I understand that there's a need to stand behind any given thesis, but it seems to me that there is often a lack of distinction between "I'm claiming this to be true primarily based on my experience" and "I'm claiming this to be true based on widely-accepted external factors, like peer-reviewed papers, industry standards, statistically-significant trends, etc.".
When people don't meaningfully differentiate between those two positions while communicating, it passes the burden of deciding which claims fall into which category onto the reader. And since I'm then unable to distinguish if the writer themself recognizes that difference, I find myself less easily able to give any of their claims the benefit of the doubt. That isn't a recipe for taking their advice or conclusions to heart.
I think you summarized it better than I could. When stating facts, be assertive and provide source. When stating opinions, state them as opinions, not facts.
As a reader, I wanna chuck the whole thing out of the window.
This is pretty common place - Harari's Sapiens suffers from this behavior excessively - I cannot read it and I don't understand why people like this book so much. Full of unsubstantiated claims.
I appreciate you saying that. I haven't read Sapiens, but since we're on HN, I figure it's worth mentioning that I think Paul Graham's writing wanders into this territory a lot. Hackers and Painters has been sitting only half-read on my shelf for a long time because I got too frustrated with it to continue for that exact reason.
When people don't meaningfully differentiate between those two positions while communicating, it passes the burden of deciding which claims fall into which category onto the reader. And since I'm then unable to distinguish if the writer themself recognizes that difference, I find myself less easily able to give any of their claims the benefit of the doubt. That isn't a recipe for taking their advice or conclusions to heart.