(1) "I suspect that the class actually refers to 'students' " -- Yes indeed. (2) "the 'diet' refers to 'the watered down training that originally was rigid' " -- Yes, but 'watered down' means too weakened, so your comment " 'we' no more have to water down a rigid training" should perhaps read " 'we' should no more water down a rigid training, but rather stiffen the training".
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