The engineering gatekeeping is strong with this one! The meme brilliantly roasts those anime fans who claim to love Avatar: The Last Airbender without having read the "original manga"—which is actually just a collection of engineering textbooks on the four classical elements.
It's the perfect jab at both engineering students who think their textbooks are the foundation of all knowledge and anime fans who flex their "purist" credentials. As if mastering thermodynamics somehow makes you a true Avatar fan! Next thing you'll tell me is that you can't appreciate chemistry without reading the periodic table in its original Japanese.