From a purely utilitarian standpoint, the attempt to label a publisher is an attempt to categorize quality for marketing purposes. The more accurate the label, the better indication of the quality of the product.
The problem isn’t with the vocabulary. The problem is that publishing is an industry in flux. At one stage in publishing history pamphleteer was a pejorative, but pamphleteers also produced classics, ie Thomas Paine’s “Common Sense.” Recently, so called traditional publishing applies as much to celebrity drek as to quality literature, so this isn’t really about quality either.
The identification by the public of the publisher “type” is the duty of the publisher. The publisher has to communicate to its audience who they are and what they do. A good publisher will be able to do that. A poor one won’t.
Publishing is about providing words to the public. The hope remains that despite the categorization of the publisher, in the flood of words, quality will still float.