Young Justice (Spoilers)

[The Bushranger]

No; it counts as war, or at the very least, self-defence. Black Beetle is an enemy combatant, who was attempting to kill Blue's scarab; it was proportionate retaliation. Black was just less resistant to the same attack method, as he was 'on mode' instead of symbiotic with his scarab like Jamie is (which likely made Blue's retailiation more powerful, too).

(Also, it's entirely possible that Black's scarab wasn't sapient (which is the word you're looking for, not sentient) due to having, presumably, never been 'crashed'.)