Calligraphers are not simple, just write beautifully. Many of our humanistic things need a high degree of ideological convergence or another peak to be called experts. It is not just a formal existence that can be called an expert. For example, in other industries, we can imitate a piece of porcelain with modern mechanical techniques. It can even be said that many mechanical techniques are more exquisite than manual ones, because machinery has precision that cannot be achieved by hand, but what is made by machinery is always mechanical and cannot be called pure manual art, and those ceramics are indeed made by hand.
These beggars in the street may write beautifully, but they don't know enough about calligraphy. For example, what is the significance of calligraphy for its historical development? We don't know enough about what's behind it. Of course, it is not that all street beggars know nothing but writing. It just means that in most cases, they don't know enough about the things symbolized behind these calligraphy. A calligrapher doesn't mean that he can be called a calligrapher just because his handwriting is beautiful. He still has many ideological things.
Simply pursuing form can't reach the essence of this matter. There are many things that are true in our real world, but if we think about them carefully, we will find that they are not necessarily true. Existence is also a hot topic in philosophy hundreds of years ago, so that many people don't understand whether it exists or not.