Because the definition of meme
The Oxford Dictionary's definition of a meme you meant to say.
For example, Jana Zündel (german article), a german meme researcher, stated that a meme always includes a recontextualisation. The Wiki page lists key characteristics such as intertextuality and cultural evolution.
There is a screenshot from reddit posted here earlier today, do you think that's a meme? Can you take it, put it in a new context and have it keep its original context as a reference so that the new post would create a new idea building on the context? Or is it just a random story, maybe funny to some?