I think there's a significant distinction, at least among younger generations: memes like "old man yells at cloud" (or "surprised pikachu") aren't used to make you laugh. It may produce a short smile sometimes or it may have made you chuckle the first time you saw it but it's so widely known at this point that it acts more like a shorthand for a shared cultural context. The "KEKW" emote the article mentions falls into this category: yes, it's used as a reaction but like an emoji it's neither to be understand literally (you're not literally cry laughing like a dolphin) nor is it meant to be hilarious, it represents that specific reaction - and more likely than not in an ironic way.

I've seen older people (elder Gen X and beyond) belly laugh at "stale" memes and even multiple iterations of the same meme template but not so much for younger people (young Millenials and below), the same way you wouldn't laugh at a Shakespearean metaphor that has become a regular turn of phrase. I think on the whole, thanks to the evolution of memes on social media (e.g. the entire iterations of "deep frying" that went through various forms of maximalism, minimalism, absurdism and deconstruction, e.g. "Steamed Hams but ordered by phonemes") many younger people don't think of memes as "jokes" as much as "toys" to experiment with as a form of self-expression. I think there may be another generational divide between Millenials and Gen Z where Millenials will more readily use memes and "GIFs" as a form of canned reply but I'm too out of touch to analyze that further.