In that case the issue is that it’s user generated content. Just as you’d cite the references listed after a Wikipedia article for the source of that information rather than Wikipedia itself, Wikipedia policy favors references to established publications over those compiled by users in a manner similar to Wikipedia itself.
For the information to be verifiable, its original source has to be both clear and reputable.
For those worried about blocking certain viewpoints, it’s important to note that the sources on the list aren’t there for the unpopularity of their opinions, but rather the frequent publication of misinformation. For instance, Fox News, despite its frequent bias, is not one of the publications on the list.
As others have noted, the list can essentially be summarized as state-sponsored, tabloid, and extremist media outlets that, intentionally or not, have editing standards that result in misinformation on a regular basis.