Unfortunately, the alternate option was not “let them stay hostage a while longer”. It was “let the hostages die”. And maybe that would have been the more ethical call. But let’s not delude ourselves that they could have been kept alive any other way.
I think it’s likely really surprising to learn/experience that feces of a breastfed baby (and to a lesser extent formula fed babies) don’t smell like shit. It’s natural to want to share a surprising learning. Might also be good to be forewarned the milky smell ends once normal food is introduced.