[VietVet]

Also, as I understand the reports of the find, that victory stele inscription only recorded that the King of Isreal who was defeated considered himself “of the House of David.” While this is the first (and so far only) mention of King David outside of the Bible, it does not exactly prove his existence nor the historical role assigned to him by the biblical texts.

[SunkenCiv]

Actually, that’s exactly what it does.

[Antoninus]

While this is the first (and so far only) mention of King David outside of the Bible, it does not exactly prove his existence nor the historical role assigned to him by the biblical texts.

It doesn't prove it. However, it does provide very strong evidence for it. With archaeology, circumstantial evidence is generally the best you can do, and as circumstantial evidence goes, this is a lot stronger than most of the other claims put forward on the program.