There is a genetic condition where cilantro tastes like soap to about a quarter of the population. Washing kids mouths with soap is/was a common punishment for saying dirty words. Collective punishment is a war crime according to the Geneva convention.
Is putting cilantro in a communal dish that will force people to essentially be punished by having soap in their mouth technically a war crime?
Only if you’re at war with neurotic foodies and your country is party to Protocol XVIIIc of the Geneva Conventions regarding taste-based psychological warfare.