Little child's diary:
Why? Why? Why? Why?
Why? Why? Why? Why?
This is derived from the first line in the famous 2006 Jay Chou song Listen to Mom: Little child, do you have lots of question marks? It was nothing special 'til Tik Tok came along. Many video makers use this line as an equivalent of this, which has brought memetic status to the line. Several derivatives of this line, like the intentionally swapped version in artist commentary, are just as popular as the original meme.
Basically, all a child does in this meme is bring up question marks--lots of them. Hence the visual joke.