The but, in this case was meant to indicate that, while I am on their side in regard to the violence that occurred becuase it was unjustifiable regardless of what started the interaction, I would not be surprised to find put that he downplayed that detail…
It’s ‘unjustifiable’. So why link that to assuming the victim was obfuscating the truth? In the same sentence, you are absolving the victim of blame while also claiming that they lied.