In a context like global politics, where you can never even hope to have any access to any actual "facts", there are no arguments - only manipulation of "opinions". So the agenda of the author is the ONLY thing that matters.
And how do you know author's agenda? From what other people with their own agendas write about him? Also, any information that's closer to political labels ("a communist", "a right-wing somethingsomething") than to actual details about him ("spent 20 years publishing anti-soviet writings, focusing on corruption in the government", etc.) is of negative utility - political labels are bullshit and only lead you to assume things about people that are not true.
Seems quite reasonable and very different from Pipes, the website owner.
Understanding the typical biases of a given source can allow you to better watch for certain flaws in their arguments.
And also prompts reader biases and red herrings.
Watch for — yes. But this often leads to prejudice instead.
Usually it only leads to a reader reading what they already believe into the text, instead of engaging with what's actually written.
Well, you have to confirm they are of your same political party before you give any consideration to their arguments. If they are from the other party, even reading the piece would clearly be a waste of time because they are wrong.