That collection of posts/comments is highly misleading.

Better just to search for the subject on reddit.

Picking one entry at random: ordinary differential equations. https://www.lesswrong.com/posts/xg3hXCYQPJkwHyik2/the-best-t...

The corresponding reddit search: https://old.reddit.com/search?q=ordinary+differential+equati...

Draw your own conclusions. From any source, that's what you'll have to do in the end. In this sample, it happens I've skimmed the lesswrong thread's recommended book and thought it looked much more interesting than the text I learned from years before (Boyce & diPrima). The reddit thread seems pretty barren in glancing through the results summary.