Just like some factory rifle barrels are good, some $20 dial calipers have been good.
These days I do not waste my time with barrels that might be good. I cut threads and chambers and use select match barrels that have been stress relieved and factory lapped.
I am not buying any more $20 dial calipers.
I like my 505-675-51 Mitutoyo dial calipers.
The word 'forum" does not mean "not criticizing books."
"Ad hominem fallacy" is not the same as point by point criticism of books. If you bought the book, and believe it all, it may FEEL like an ad hominem attack, but you might strive to accept other points of view may exist.
Are we a nation of competing ideas, or a nation of forced conformity of thought?