And whosoever shall offend one of these little ones that believe in me, it is better for him that a millstone were hanged about his neck, and he were cast into the sea. And if thy hand offend thee, cut it off: it is better for thee to enter into life maimed, than having two hands to go into hell, into the fire that never shall be quenched: (Mark 9:42-43)
Moreover, public stoning was the normative Biblical form of capital punishment, versus antiseptic executions by the state, and communal stoning corresponds to crime also being against the community in general, and serves as a deterring reminder to all of the consequences of sins (and of false testimony), as well as providing a better sense of justice.
Wasn't that thought to be hyperbole of the type that was common of the language at the time.