The difference is that those amateur sunset/lighthouse/barn photos here are never put forward as "art" with or without a capital A. However, when you title yourself "The Painter of Light" or some such pompous nonsense you had better be able to back it up. The only thing Kinkade was able to back up was the truck he used to haul off a lot of unwise people's cash. He sold his "paintings" as "art" to people unsophisticated enough to think that what they were buying was investment grade - they had heard the terms "limited edition", "original oil" and "collectible" before and when they were tacked on to what he was pumping out, they thought they were not just buying a pretty poster for the wall, but something they could pass on to their kids who would get not only aesthetic benefit but financial benefit as well. There was an implicit association between his work and other actual investment-grade art (Picasso, Van Gogh, Vermeer) - it had to be "art" to make it investment grade. So he himself created the false impression that what he was producing was "art". The reality was of course a different matter altogether. As you said before, he was making home decor at best.
The massive hate-on for Kinkade has nothing to do with jealousy - it has to do with the combined effects of his incredibly disingenuous and/or corrupt business practices and the butchering of actual art that he executed. It's not because his work fails as "modern" art, therefore isn't "art". For me, painting starts losing steam somewhere around post-impressionism and by abstract expressionism I'm about disinterested, and most truly contemporary work leaves me antarctic-grade cold. If Soviet Realism had a torrid affair with Impressionism, and the love child that was born showed that in actual fact they were first cousins by combining the worst sins of both, that would be Kinkade: "It's fuzzy, has dramatic light that makes no sense, and spouts dogmatic, 'uplifting' propaganda at every turn!".