This is by design is because browser manufacturers think/agreed, that beneath web editors, producers and developers the <h2> is commonly treated as the visual more important heading and headings in the content documents should then ideally start with . That is why <h1> font-size is not default bigger inside <article>, <aside>, <nav>, <section> tags.
I’ve never experienced H2 to be larger than H1 in such usage, but rather the same size. Are you sure there aren’t any CSS affecting your result?
From a stackoverflow reply:
Thank you!