There has always been. This is not additional subject. Politics has always been one subject, with different text for each grade, either it is Maxism, Materialism, Deng and so on. This is not a new subject, just new text added to Politics.
what do you mean, the courses with social political education? It was always there. From my education experience in the late 80s to 00s. But to be honest no one is ever taking it seriously and it's obviously a joke to students.
No, no. Single politics course, they do exists, but never single Maoism course, single Dengism course, etc. Even in colleges and universities they're combined into one single course. This time it's different, China is having single Xi-ism course.