Take the time to read the ToS and Disqus guidelines carefully. What they say is that each person is responsible for their own actions and words. Channel creators and mods can deal with violations if they chose to do so, however it is not a requirement. It is the responsibility of Disqus employees to deal with violations. Disqus employees allow people to believe this misconception because it takes the heat off of them when they do not enforce ToS or policy. Disqus employees are responsible for dealing with report user complaints, harassment and any other problems. Channel creators and mods doing so is optional.
The reason this is not enforced by Disqus employees is because Disqus employees responsible for dealing with complaints  have formed friendships with some community members which creates a conflict of interest that interferes with them doing their job correctly.
Disqus needs to have employees who do not have channels and do not interact with the community handling these complaints so they are dealt with appropriately. As long as Disqus employees handling the complaints are friends with community members the problems will not be dealt with appropriately.