Putting science aside, how can I be confident that the basic facts presented in, say, a NYT article, are correct? I can trust the reputation of the NYT as an institution, and I can also trust that any inaccuracies in the article will be called out by other publications. But if I feel everyone's in on a conspiracy to push a particular viewpoint, then I need to anchor my knowledge in a different institutional framework - even if that might just be a random Facebook group of strangers, or my weird uncle, or a niche radio station.
This, incidentally, is why the censorious push against "disinformation" is misguided in principle. It's sweeping the underlying problems under the rug in the hope that they disappear spontaneously. In an open society, truth can only be established as a result of public discourse, anything else is just the representation of the perspective and interests of some authority. Whatever its source, the seemingly growing distrust in public institutions will not disappear simply because we make social media companies remove its most obvious symptoms.