Council of Laodicea and Scripture
Why did the Council of Laodicea not reaffirm the same canon of Scripture from the earlier Council of Carthage? It specifically doesn't include the deuterocanonical books.
The "Council of Laodicea" was a regional synod and not an ecumenical council. Therefore, it is useful in terms of ascertaining practices of the time period but nothing it decided is considered an infallible decree.
Canon 60 of the synod deals with the books of Scripture. This canon is not held by anyone to be a definitive list. The canon's listing of the New Testament omits the book of Revelation. It also would not be entirely accurate to say that it does not include the deuterocanonical books. It's listing of the Old Testament includes the normative Jewish canon plus the book of Baruch and the letter of Jeremiah.
However, all of the debate over canon 60's listing of books is most likely for naught. The authenticity of the canon is considered spurious. It is missing from many ancient manuscripts and is believed to have been added on at a later time.