Not only was the course not "too hard", the author give plenty of indications that the course is actually pretty easy. The quizzes everyone was cheating on were

Not only was the course not "too hard", the author give plenty of indications that the course is actually pretty easy. The quizzes everyone was cheating on were open-book. At one point, a student in the group chat recommended that people look things up in the course textbook: "The best advice was a student telling everyone they could just go to the website for the textbook, then control-F in the textbook and search for words in the question to find the answers. I mean, ya. It’s in the textbook." This does not sound like a difficult course to me. I have taken courses where it's rather trivial to ace the online quizzes by looking things up in the textbook (I am taking one right now, in fact). Students who can't even do this and resort to sharing the answers in a group chat must have become incredibly jaded about their education. I fully agree with the author's decision to both sanction them for cheating and give them a second chance to engage with the course material. It was very satisfying to see that all of the effort paid off in the end.