EDIT: A lot of you are reading into the tweet while still somehow agreeing with the overall message. No one is saying we should eliminate music programs or that we should teach toddlers about healthcare plans. The tweet is making this thing called a --checks notes-- joke, that also conveys the message that schools could teach more practical skills that young adults will need going forward.
What does hot cross buns mean in this context?
It's a super basic song that people tend to learn early in music. It's three notes and a very simple pattern.
HOT
CROSS
BUNS
HOT
CROSS
BUNS
ONE-A-PENNY TWO-A-PENNY
HOT
CROSS
BUNS
When I was in school, that was just the first song they'd teach us on the recorder so I assume it's meant to be the teacher pushing on with the lesson instead of listening to the student.
It's one of the first songs taught on a recorder.