Except that none of these things conclusively prove it is false, they merely are evidence that it could be. A fake image means nothing other than that no image exists or if one does, that no one had access to it. The lack of evidence for a person's existence is not proof that they didn't exist, only that they lived an unremarkable life that was not noteworthy enough to leave a record. As for the timeline, he had 38 years to get the recipe between learning to cook and introducing it in his cafe. Again it doesn't disprove that he got the combination of herbs and spices from someone else.
You still seem to be having a problem between "unable to be proven true", and "unable to be proven false".
Just because something cannot be proven to be true, doesn't make it false. Consider trying to prove what you ate for Breakfast last Friday. Unless you were lucky enough to go out and keep the receipt or happened to film yourself eating it, how exactly would you go about proving the truth of it?
I disagree, they make it clear that they have been unable to prove any of it as true, but also they can't provide evidence that totally disproves the claim either. The correct stance is at that point to say it is Unproven.
No, your claim of it being "an obvious fabrication" is jumping to a conclusion that the evidence does not support. You are making an assumption based on your views on the evidence, not based on what the evidence itself is. Snopes does its best not to jump to a conclusion it is unable to fully support. Blasting someone for refusing to make the same jumps, and weighing the evidence the same way that you did is very poor skepticism.