Once this provenance trail, that humans use to trace claims back to an accountable source, is dead and buried under automated sludge, "just pick people to trust" stops working as a viable strategy. How do you even tell who is actually talking?
Now, the bigger problem happens if some of the trusted institutions and people go bad, for various reasons. If the NYT got bought out by Alex Jones, it might start mixing in lots of slop - but this is also a pre-existing problem.