Misusing the sitemap implementation was a bad idea and broke for every
major update.
I now finally migrate to custom implementation which should remove the
issues for future.
This is not nice, we should use have within query but that would mean we
need to create our own processor.
That's why I hotfix within the existing one.
This way multiple joins are possible.
As multiple joins are possible, TYPO3 can add pages to the query and
therefore respect the enable fields.
Hidden pages will therefore not be part of the result, fixing
inaccurate count for none published pages with assigned categories.
Also the TypoScript communicates what should happen.