If I were to use the "fetch" command for adding commentary, the text all appears on one line. I wound up having top manually copy and paste from the original page.
So DeviantArt allows commentaries to contain HTML but we don't. Currently we deal with this by just stripping out all the HTML, but that produces poor results when the artist uses a lot of HTML. issue #3137 fixes it by autoconverting the commentary to DText syntax. This should work better in most cases.