Painting is not just for the professional. Painting can be a pastime or a hobby too; and pursued for the satisfaction of simply trying something one has always wondered whether or not they could do. There is nothing wrong with being an amateur at painting. It is a beginning. Many professionals were once amateurs.
Besides, the word amateur comes from the Latin word, "amator" which means . . . "One who loves." That certainly gives you a better feeling about the word amateur. The amateur painter is not even thinking of selling his or her paintings. Painting is done solely for the enjoyment they love along with them being a bit sentimental about their work. Although that does not mean there won't come a time when selling their art does become desirable. Eventually they may want the satisfaction of knowing that someone likes their art so much, that that person is willing to pay to have their work.