Well the difference is you're a random commentator and the other is the sitting US President. One person's words matter more than the others, at least globally, I'll leave it as an exercise to the reader to figure it out.
I don't care if the almighty comes down, waves their tentacle and says "let there be light" - if it's still dark after their pronouncement, then anyone who bet a light would appear should lose the bet.
Trump's declaration that he is taking over Venezuela fits pretty comfortably within this category.
In your terms, a light did appear. You're right that the light is not directly connected to the utterance. But since the argument above that there was no invasion is premised on a lack of intent to invade rather than on the invasion not having happened, the utterance disproves that.
