Hi Jonathan, can you try the following please...
<ObjectFilters>
<ExcludedCodeNames ObjectType="cms.documenttype">%article%</ExcludedCodeNames>
</ObjectFilters>
Just an update I tried this, but it didn't seem to work for me either. So I would recommend for now to add something into your ignore file.
So if your using GIT, add the something like \CMS\App_Data\CIRepository\@global\cms.documenttype\cms.article.xml
Now this won't speed up Kentico CI, but at least those Page Types won't be tracked.