[30f0fn]

The book contents are FREE! Look away if you're offended.

[dkarp]

They weren’t attacking the author. It’s a valid argument regardless of the cost of the book. Free doesn’t mean you can’t criticize anything.

[macintux]

There was an accusatory, hostile tone that I personally found off-putting and not worthy of an HN discussion.

asicsp’s comment[1] was much more useful and neutral.

1: https://news.ycombinator.com/item?id=26074429

[cinntaile]

He stated his experiences with mathematics and computer sciences books and provides arguments for why he thinks this is not a good approach. I really can't see where he is being hostile or accusatory?

[chapium]

Tone policing on a textual medium isn't helpful either.