You know, for such a potent piece of faith-ending gnosis one would be proud to take responsibilty for it... rather than hiding oneself as "anonymous".
Are you that fearful of persecution when every public school and nearly every college and university teaches that the Big Bang, and Evolution is true? When Hollywood regularly ridicules fundamentalists like me, and yet our only militant response is to homeschool our kids? Wow, that is a dreadful and deadly act on our part, isn't it? You're petrified at that, aren't you?
So, do you rightfully fear persecution? Of course not.
So why the Hit & Run?
With that, here's my response to your meme.
Let's assume that there is a Sumerian text on creation that predated Genesis (I'm not aware of it, and it wouldn't huirt my faith anyways to know that it exists). Just because the story in it predates the Bible doesn't mean that it's the original.
It was previously thought that Jericho didn't exist, but when it was discovered, not only it prove the Bible, but it was arguably the oldest city found.
Now, if I were to use that as evidence for scripture even to say (which I wouldn't), that "Since the Bible says it's the oldest, and Jericho is listed as the oldest, then that proved the Bible as the word of God". I'm sure you'll reply by saying that the next archeological find might just be the one that would supercede Jericho by a kilometer/mile.
So, just because it predates scripture doesn't necessarily prove the Bible copied it, proving that it isn't.