As he commented when I pointed out his untruthfulness already in the first paragraph of the article you recommend:
"I don't take this nearly as seriously as you do.".
Just some very few more comments to give a glimpse of the nature of his writings:
On "The centerpiece of anthroposophical belief is [...] the access to esoteric knowledge available to a privileged few". This is a typical ideological kliche in "enlightened" polemic against spiritual views.
Probably everything Steiner wrote or said in lectures is published in German online in addition to being published in print. Probably all of it that has been published in English translation also is accessible for free online in English.
"Jazz and popular music are often scorned at European Waldorf schools, ..."
From "The art of turning white into black" by a Swedish Waldorf teacher:
"In my Waldorf school I teach children of all colours. We have a lively cooperation with a sister school in Soweto and organize daily works where the pupils collect money to help them. Of course the pupils have much gymnastics and sports (actually more than most of their friends in public schools). Of course they sing and play much modern music, also pop and jazz. The dialogue between teachers and pupils is open and warm.
My fellow teachers and I know that karma doesn't mean any fatalism: it teaches us to take responsibility for the here and now, to take every individual pupil seriously, trying again and again when we meet difficulties."
On "Natural processes, historical events, and technological mechanisms are all explained through the action of spiritual forces" just to take one of many more possible examples of P.S.' reliability and "truthfulness", see Anthroposphy and Ecofascism Examined, p. 19-20.
He lost his credibility as a consistently reliable source on anything related to anthroposophy many years ago, both as a demonstrably reliable source on publishes sources, as well as a truthful source in a deeper sense of the what Steiner said or the context of it at different times.
Try "On the stories of P.S." again.