The originators of HTML were scientists who wanted a standard means to share particle physics documents. They had little interest in the exact visual form of the document as seen on the computer screen. In fact, HTML was designed to enforce a clean separation of content structure and graphic design. The intent was to create a World Wide Web of pages that will display in every system and browser available, including browsers that "read" Web page text to visually impaired users and can be accurately interpreted by automated search and analysis engines.
In casting aside the graphic design and editorial management traditions of publishing, the original designers of the Web ignored human motivation. They were so concerned about making Web documents machine-friendly that they produced documents that only machines (or particle physicists) would want to read. In focusing solely on the structural logic of documents they ignored the need for the visual logic of sophisticated graphic design and typography.
For example, most graphic designers avoid using the standard heading tags in HTML (H1, H2, and so on) because they lack subtlety: in most Web browsers these tags make headlines look absurdly large (H1, H2) or ridiculously small (H4, H5, H6). But the header tags in HTML were not created with graphic design in mind. Their sole purpose is to designate a hierarchy of headline importance, so that both human readers and automated search engines can look at a document and easily determine its information structure. Only incidentally did browser designers create a visual hierarchy for HTML headers by assigning different type sizes and levels of boldness to each header element.