I can't explain
Meme-splaining seems like a dubious genre, a bit like explaining why a joke is funny instead of telling it. When a meme is specifically playing with the impulse to explain, it's even worse to launch into a meta-explanation about why that impulse is so meme-able. So the meme where the girl is shouting into the boy's ear at what looks to be some kind of music festival probably doesn't need any comment, but in the spirit of the meme itself, I'll just go ahead.
When I first saw this circulating on Twitter, it wasn't entirely clear to me whether the idea was supposed to be that the speaker is saying something trite, something boring, or something over the boy's head. That ambiguity seemed to be the point, looking at all the variations in aggregate. It seemed like an obvious metaphor for Twitter itself, where so often people are shouting earnestly or insistently into the feeds of people who aren't paying much attention. So doing the meme becomes inherently self-deprecating, highlighting how we know that what we mean to say rarely gets across.
But there is perhaps more to it: This Twitter thread contrasts the meme with a predecessor, in which a man speaks and a woman stares off into the distance. With that version, the joke is "about the ways men feel entitled to your time and physical space"; accordingly he is generally saying something obvious or obtuse. In the version currently circulating, though, people are mainly using it to "represent sincere excitement about topics they love." The contrast, the thread concludes, shows "whose speech is treated as valuable, but also the yearning for sincerity after such a long era of cynicism in pop culture."
While the first half of that seems right, the second half reminds me of the many "return to sincerity" takes that have been floated over the years in an effort to cancel postmodernism. These tend to attribute cynicism to "culture" rather than "capitalism" and suggest that irony is some kind of character flaw rather than a protective response to economic conditions and how they deform our lives. If only people weren't afraid to be earnest and enthusiastic, we could fix all our crises and return to a golden age of truth. But the meme itself is an inherently ironizing form.
What seems moving, at least to a hardened cynic like me, is that people keep participating in memes, trying to express themselves in a form that tenuously balances difference and repetition. My individualistic expression is immediately negated by the conformism inherent in memes, but it is precisely irony that negates the negation. There is no such thing as a sincere meme; that's just propaganda.