He's not much of a biblical scholar if he can't think of an instance in which Jesus is reported as writing on the ground. Literate? Yes. I'll admit He didn't use parchment or papyrus in that instance, but He could write.
Reading? I seem to recall Jesus reading from the scroll of Isaiah when He was in Nazareth. Jesus is presented in the Bible as able to read, and literacy was, in fact, widespread among the Jews, even 2,000 years ago. Biblical scholars should include the Bible among their readings.
And yet the Bible outsells all other books, including his, by far, in the old. I think he’s just jealous...: )