They don't do anything at all except well, influence?

Correct.

Their function is to merely amplify and relay whatever propaganda they are given to their audience.

Sometimes, in a rare display of critical thought or original thinking, they might add their own two cents to The Message, but their role is just to extend the reach of the signal.

Edit: To be more generous, I suppose you could consider them as curators, who garner an audience because their particular flavour or offering of filtering and selecting content meets the wants of the viewers.

While other channels might do research, offer insight, invite qualified and experienced experts, and provide commentary, what the former seem to do is merely show their audience "here are some things that might interest you" and leave it at that.

They don't do anything at all except well, influence?

Correct.

Their function is to merely amplify and relay whatever propaganda they are given to their audience.

Sometimes, in a rare display of critical thought or original thinking, they might add their own two cents to The Message, but their role is just to extend the reach of the signal.