Thomas might have been thinking his writings should be used in a similar manner. In simple terms they were rather useless, perhaps in error, not true, or even complete nonsense, etc.
A writer that really believed what he wrote, and that had even more wonderful information revealed to him, would probably have said something more like… " my writings are inadequate to reveal the complexity of the essence of God but I did my best. And now I will continue writing using the new found information as revealed to me." Thomas’ defeatist reply sounds like the reply of someone who had been told what he wrote was all nonsense. Perhaps even that his particular God concept, with all its confusing attributes, did not exist.