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.