Because I don't believe Kincaid's work is intended to be a tribute to the glory of our Lord. It is intended instead to make money for Kincaid. The use of religion is OK for the first premise, but not the second, IMO.
Beyond that, it seems questionable whether Kincaid is a good Christian, or whether his work reflects well on Christianity.
Very succinctly put, although I would add that I am in no position to question Kinkade's personal walk. That is above my pay grade, so to speak.
So, is that grounds for an FBI investigation?