This part of the ArticleInfo code is very old and predates the introduction of tags in MediaWiki. In XTools 3.17.11, we'll be introducing a new API endpoint for (semi-)autoamted edits made to a page. This API uses a dedicated query that fully respects tags as well as edit summaries. Likewise ArticleInfo (which goes through every edit one by one, as opposed to dedicated queries) should also respect tags.