You were not sent to scare people away. Soothe and do not scare away. He was patient when they were coarse. But it is not permitted for us to be patient with them in such cases. That was because people at the beginning of Islam needed to be brought close.
People are unanimous about that.
Once Islam was firmly established and Allah had given it victory over all other deens, any such detractor that the Muslims had power over and whose affair was well-known was put to death. A case in point is that of Ibn Khatal and others whom the Prophet said should be should killed on the Day of the Conquest and those among the Jews and others whom it was possible to kill by assassination. There were others who were captured but rectified their behaviour before they came into the Prophet's company and joined the group of those who manifested belief in him. The inward parts of the hypocrites were veiled and the Prophet judged according to the outward. Most of these things were uttered by them in secret and among people of their own sort.