Disqus provides the engine, the web sites provide the mods and obviously individual sites and different mods within those sites have different rules and tolerances.
Disqus solved a big problem ie it eliminated the need for commenters to register at every site. But it is a very flawed solution otherwise. For example, its threading model/implementation is poor.
Like so many monpolies, they have abused their power. Downvote totals are, inexplicably, no longer displayed. Supposedly enough downvotes will eliminate a post or flag it for mod review but who knows what the criteria are?
Even more inexplicably, there is no ignore/block function. For a single-login commenting engine that is used extensively across the internet, this borders on the insane considering the number of trolls that infest the ‘net.
But here’s the dirty little secret: web sites want to be ‘sticky.’ They want eyeballs, impressions, minutes spent, etc. because that means ad revenue. Troll battles are annoying and futile but they keep the hotheads returning to do battle for hours, even days, thus boosting web stats and ad revenue.
Facebook comments are hardly the solution, since a fake account for troll purposes is easy to establish and FB will do nothing to combat them even if they are led by the hand.
PS - I have never understood why Hot Air has not changed or improved its comment system. There are a small number of trolls there that derail every thread and, sadly, the HA users take the bait every time.
It is even worse than that.
In 2014, Disqus decided to remove the "downvote" arrow count on all comments. Only "upvote" arrow counts would be displayed.
Users complained to Disqus, and they ignored their users and kept the policy.
https://help.disqus.com/customer/portal/questions/6050471-why-was-the-downvote-count-removed-
And I will tell you why they did this: the liberals were getting murdered in the court of internet public opinion.
I saw many discussions (Politico, The Hill, etc) where the liberal comment would get hundreds of "downvotes" and only a few "upvotes." The conservative (and logical) comments would be upvoted like crazy. Those people who tried to praise Obama, abortion, homosexuality, trans-gender garbage, socialism, "free" Govt handouts, etc. - all got their butts handed to them.
And they did not like it one bit.
So they complained, and complained, and complained. Liberals on the Disqus board joined their effort, and that was that.