The Anabaptists
Conclusions
Why were the Anabaptists so universally reviled? The answer is simple, but it goes to the very heart of the nature of the Protestant Reformation: they defined themselves as a church apart.
The Catholic Church had faced the choice over a thousand years before: when Christianity succeeds in a society, do Christians stay apart from the general society, or do they accommodate themselves to the general society? The Anabaptists chose the former path; the Catholic Church in the time of Emperor Constantine chose the latter. So, too, did the Lutherans and Calvinists of the sixteenth century.
By choosing to be a church apart, the Anabaptists became an alien society. The degree of separation was a matter of great importance within the various Anabaptist sects, but was of little importance to the rest of society. They would not serve in the military. They would not take oaths. They lived apart and did not share in the economy, the social events, nor even the ordinary obligations of citizens and subjects. This made the Anabaptists suspect, right from the start.
The violent and lurid events at Münster naturally gave ammunition to the opponents of Anabaptism, but even without that, the Anabaptists would have been (and were) reviled. Their very existence was a condemnation, for if you weren't Anabaptist you were by definition not within the true church. No one likes to think that about themselves, so the natural thing was to condemn the Anabapists. Especially in the first couple of generations, Anabaptist preachers were out actively criticizing the rest of the world and inviting people to leave their church (whether Catholic or Lutheran or Calvinist) and join theirs. In other words, the Anabaptists were not only a passive but an active threat. Moreover, Anabaptists were blamed for supporting other disruptions, including peasant revolts.
Nor did the mistrust of Anabaptism recede with time. In general, if times were peaceful, Anabaptist communities might be left alone, but in times of crisis, either economic or political, Anabaptists found themselves persecuted, in country after country, century after century.
They did not contribute directly to Protestant theology, but they did indirectly because the other Protestant theologians found that they had to formulate responses to Anabaptist positions. Thus, from Luther onwards, they had to find a way to justify infant baptism, subservience to the state, serving in public office, ownership of private property, and killing as part of military service. In the eyes of many during the Reformation era, the piety of the Anabaptists was seen by some as a kind of ideal against which other Protestant churches was measured. Few would go so far as to join an Anabaptist church, but Anabaptist criticisms of other reformed churches resonated and required response. One response, of course, was persecution; but the other response was to develop Protestant ideology more fully than perhaps it would have otherwise.