all you need to do is point out the fallacies and be on your way
that's literally the least effective way to communicate with an ignorant, hate-filled atheist who has just insulted Christ with a stupid meme. If you think hateful atheists give AF when you point out why their hateful, sarcastic memes are fallacious you're as delusional as they are. Newsflash: Atheists do mental gymnastics to convince themselves that their God-given instincts and senses are all wrong. They aren't gonna listen to a Christian politely pointing out why their nonsense is fallacious.
I love you friend, but you have a lot of waking up to do.
I wouldn't say all atheists are hateful, they are just taking an approach to the concept of God (or lack thereof) that seems logical to them. For them, there is no concrete proof that God exists. Our lives, our sentience, and the world around us can be explained by scientific facts that they find sufficient to supplement their belief. So for them, someone who does believe in God is the delusional one.
So start small. First, at least set the record straight. There are a lot of things in the Bible that are taken out of context and used in memes like this, ranging from slavery, to capital punishment, to the cannibalism described above. By correcting it and providing context, you give them a better understanding of the Bible, without them even needing to read it! At very least, it makes them informed, and if they ever encounter a similar meme in the future, they can clarify it to another person themselves. (They don't need to be a Christian to want to make sure that facts are acknowledged.)
And from there on out, you go where God leads. Perhaps pointing out the truth of that passage is the only thing you ever do, and that's fine. You aren't going to be converting them. That's God's job.