[wolverine876]

I think both are essential: Evaluating arguments on their merits is obviously important, so I'll focus on the second method.

We live in a world flooded by propaganda; we are committing political and social suicide by not addressing it. One powerful method of addressing propaganda is to identified beneficiaries - the people behind it are necessarily doing it for their own benefit.

And at the same time, evaluating arguments on their merits exposes us to propaganda: First, a well-known reason: it is much easier to make up lies than to determine the truth; the propagandist can easily consume all the resources of the person looking at merits. Second, humans are significantly worse at determining merits than they imagine (says much research).

Looking at merits depends on some good faith: The person submitting the argument is trying to present a valid argument. Propaganda is built on abusing that good faith.