True… I suppose in the strictest sense of the word "painting".
A dictionary entry might read;
Painting:
1: the action or skill of using coloured pigments, either in a picture or as decoration.
2: an image created through the application of coloured pigments to a substrate.
With digital we are deciding what colour light should be emitted from any given pixel instead of choosing pigments.
So referring to it as "pixeling" might be a more apt name perhaps? But it conveys no meaning.
As with most things people need a point of reference or a handle they are familiar with that requires little or no further explanation. And in this regard the word "painting" serves well enough. After all when hearing the word "painting" no one ever says "what's that then?" we just know.
Though I do quite like the idea of referring to myself as a "pixelist"!