Comment by fiddlosopher

If you don't want pandoc's fenced divs, just choose a markdown dialect that doesn't support them: e.g.,

    pandoc -f html -t gfm https://www.fsf.org

Or, to get rid of the divs and spans altogether, disable raw HTML as well:

    pandoc -f html -t gfm-raw_html https://www.fsf.org