Mdd,
The halacha you are referring to and the Gemara it is based on are describing a hora’as sha. Not something to be implemented on a broad basis across the board for an extended period of time. If a community is sliding and extreme measures need to be taken against a person then the Halacha says the community leaders can execute someone. There is no source that I am aware of, however, (outside of the ir hanidachas) that allows killing or force on a large scale outside of the strictures of Bais Din and the normal halacha.