because people are stupid LOL Like the creator of the universe is going to give an image of himself in a tuna sandwich, especially when the scriptures make it absolutely clear that we are not supposed to worship images anyway!
Images of Christ appearing in anything is contrary to the scriptures.
If you believe in Christ, you have to believe in the Word of God (because that's where we learn of Christ), and if you believe in the Word of God, then you know these appearances are contrary to scripture.
We are even warned that in the last days people will say "Here is the Christ, and there is the Christ"
So don't believe the hype.