sphinx/clean_html.rb is used across a wide range of docs, and unfortunately I found the formatting of Sphinx docs to be very inconsistent, to the point that aggressively removing some of the markup felt the better compromise to make this code work across all the Sphinx docs.

If you change it, it's likely (but not guaranteed—that was a long time ago) to cause minor issues on some docs, but I think it's worth a try (considering I don't remember exactly why this was added and that the worst that could happen is some styling issues, not content breakage).