You need a citation proving that the Greeks had festivals in honor of one of their gods many years before Jesus was born? Um...here you go:

https://en.m.wikipedia.org/wiki/Dionysia

The meme is stupid and inaccurate because the skit wasn't representing any specific work of art but was meant to be representative of a Dionysia, aka a Feast of Dionysus. If we're going to make fun of the people outraged about this, the stolen imagery angle just doesn't make sense. Instead, maybe focus on their need to feel victimized or the amount of hubris required to assume that the opening ceremonies of an event rooted in Ancient Greek traditions was all about them.

But i digress. You, OP, and many other people seem confused because there is a long history of "Feast of the Gods" artwork. When you try to search for Feast of Dionysus, recommended searches suggest including the word "painting" which leads people to said artwork. That ends up leading you further away from Dionysia and onto tangentially related things like the painting you are referring to, "Le Festin des Dieux," which was indeed painted from 1635-1640. However, there are many paintings with this theme that bear stylistic similarities to The Last Supper. One of the oldest examples was completed by Bartolomeo de Giovanni in 1490, 5 years before Leonardo began his Last Supper.

Examples here: https://en.m.wikipedia.org/wiki/Feast_of_the_Gods_(art)

So anyway, maybe now you can all move on with your lives now.