alt Hacker NewsIf memory serves, the license is the ultimate source of truth on what is allowed or not. You cannot add some section that isn't in the text of the license (at least in the US and other countries that use similar legal systems) on some website and expect it to hold up in court because the license doesn't include that text. I know of a few other bigger-name projects that try to pull these kinds of stunts because they don't believe anyone is going to actually read the text of the license.
The copyright holder can set whatever license they want, including writing their own.
In this case, I'd interpret it as they made up a new licence based on MIT, but their addendum makes it non-MIT, but something else. I agree with what others said; this "new" license has internal conflicts.