Banning from this community won’t make them disappear from site like facebook and twitter that have millions of more visitors, but it will keep people in this community from seeing the kinds of things facebook and twitter users see.
Bad articles from bad sources are a problem that should be solved by an intelligent and active community that downvotes and leaves comments pointing out the article and/or source’s weakness. If the moderators don’t think we have a strong enough community for that this might be necessary, but I don’t think it is.