It's not the specificity of the rules that causes the non-CSS presentational hints to take precedence, it is the level of nesting in the tree. The answer to this question comes from the way CSS selectors work.
Selectors match elements in the document tree.
This happens because the H1 selector still matches the H1. It means that they can always be overridden by author CSS that acts on the HTML element that provides the presentational hint. This text is red. This text is green. This text should be green.