Justification

1.) It was fair for The Independent to use the word "monster" in the description of Karadzic due to the horrific description of the death camps run for the Muslims in Croatia and Serbia. The use of memory gives way to the death camps run by the Nazis. The journalist were allowed to 'tour' the death camps, so the use of empirical knowledge aids with the title of "monster"

2.) The title of monster is already empirically and memory justified. It is justified by authority because The Independent  is claiming to be a reliable news source and one would assume that prior research had been done. A reason syllogism can be made to describe Karadzic as a monster:
War crimes are committed by monsters.
Kradzic is a war criminal
Therefore, Karadzic is a monster

3.) Monster means a lack of any sort of characteristics that make someone human; (e.g. compassion, love, sympathy, mercy, etc.) A monster is a person who is inhumanly cruel or wicked.
While Karadzic may have started with nationalistic intentions but the crimes committed against humanity are unforgivable.

Defining A Monster

The Independent refers to Karadzic as a monster based on reports gathered from both sides. While this alone is not enough to define a 'monster' in and of itself, the sheer number of the reports must be seriously considered. The Independent uses Knowledge by Authority regarding the reports coming out of Serbia at the time. Karadzic is described as a monster much in the way most people would describe Hitler as a monster. Neither one was directly causing the violence, but terrible atrocities were committed under the orders of both, and neither did anything to stop it. The reports filed by the journalists that were 'invited' into the prisons were recorded in a way to blend both emotional imagery and factual reporting. This could have led to the distortion of some details, but the sheer number of similar reports would have overcome that.