> do not wake up kids for school; if they cannot wake up in time, let them skip a class or two, or consider homeschooling

That is a completely infeasible suggestion for most people.

I think people would be happier if we could restructure society in a way where this would be possible.

More robots are needed.

> Go to sleep only when you are very tired. Not earlier.

> In my view, everyone should always free run his or her sleep unless it makes it impossible to function in society along one's chosen profession, specialization, education, etc., or where it makes it impossible to take care of the young ones.

Is that not almost everyone? I often don't get tired till or 4 am and have to get up not long after that for work.

Do you exercise during the day? Do you avoid strong light and things that excite you when bedtime nears?

I think the author is arguing that by using alarm clocks and artificial light and otherwise caving to the expectations of society, we are wrecking our internal sleep clocks and they cannot be trusted for measurements until you have actually removed yourself from all that for a while. That includes your 4 am is sleepytime measurement.