To a degree, I agree. I have no problem treating as serious the opinions of various sites, despite what I may feel about their editorial direction. Despite the occasionally tone deaf* and explicit faoviring of wealthy interests I treat arguments from the Wall Street Journal seriously. Now I will frequently find issue with their arguments, but they are not wholly without merit either.
Same could be said for persons. Despite my personal feelings on William Kristol or Charles Krauthammer, and let it not be said they are favorable, their arguments are worth taking seriously. Deconstructed and argued against in earnest, not simply dismissed.
But should one treat with seriousness Breitbart? Should the rantings of Alex Jones be treated with anything but contempt? I’d argue no. Their actions and words have demonstrated that theirs are not worth serious consideration, that they are unhinged worthy of the manifold scorn they earn. I would dismiss outright any article from them, not even engaging with it. Outright a priori dismissal of their positions and arguments is, in my estimation, a proper response.
Not all sources are created equal. Some are worthy of outright dismissal.
*see their graphic on taxes for the ACA