Because Varg never claimed Euronymous attacked him physically, hence where would the most apparent act of self defense be?If you already read that, why would you have said that it's easy for Varg to claim self-defense when it's just his word? If you read the story, you'd have known of Snorre Ruch and others. Nobody is saying that he was justified in killing Euronymous. The killing still originated as a self-defense plan, and Euronymous did plan to kill him the night that he killed Euronymous instead. Euronymous was just too much of a coward and tried to run, and we all know that it didn't work out for him.
If you still want to debate this further we can do so further tomorrow but I think we both understand what we're both trying to convey now.