This is full of bad advice. I previously mentioned some of the problems at https://news.ycombinator.com/item?id=41026577, and past submissions of it are full of others' comments pointing out even more problems.
Not just bad and outdated advice but they also do not list some of the caveats for each of their tuning suggestions. The internet is full of such snippets and most all of them leave out the potential pain that can be caused in various configurations. People should be given enough knowledge to make an informed decision rather than stepping on landmines after a blind copy/paste/reboot. Some of these settings can be good on internet facing servers but can also break things in some circumstances so at very least people should research each option in depth.
I would suggest they instead just link to the latest NIST compliance checklist and hardening guides so that when things break at least others will have more likely experienced the pain and documented it.
In fairness I at least appreciate their efforts and intentions. There are too many internet facing default and insecure setups.
