I think the expression "dark tourism" is not much more than simple rubbish. S21 and, in part, the many killing fields are places to inform on the atrocities committed. They are a warning to us and they also honor the victims while condemning the perpetrators. These sites are essential for the struggle against the efforts to make us forget. Especially in Cambodia, this is an important issue.
To denounce people who visit these sites and pay they respect to engage in a form of "dark tourism" reflects very negatively on the poster. His serial posting about such sites of remembrance suggest that he is not simply asking questions but follows an agenda.
Are you trying to commercialize the remembrance of the victims in a new guide book?
I think you would do better be being a bit transparent about your postings. Otherwise, the members here will do good to ignore your activities.