There are necessities and there are necessities. The Lutherans eventually attained a legitimate legal standing in Europe. However, the Anabaptists did not. They were outlaws in most places in Europe. There are many reasons for this, many of them unfortunate. They were persecuted and even sentenced to death by the Reformed in Switzerland and Lutherans in a number of places. They continually fled until they settled in North America. Many of them settled in the plains in Canada and in the United States. There has only recently been attempts at reconciliation, something poor in comparison to the many tales of martyrdom in the Martyr's Mirror. You can read more about this here. After the Second World War, Lutherans had much to confess and repent of in Germany. Some who had resisted Hitler wanted to exact confession from those who had collaborated or remained passive. Wiser heads prevailed and all confessed together. One of the resistence, Hans-Joachim Iwand, claimed that that moment of confession in 1947 the German Lutheran church was at its most evangelical moment. We would be wise to emulate such confession in more areas of life than just these sad parts of the past. Surely even in the recent conflicts with terrorists and here in the United States we ought to consider a new form of repentance, and one that we all do, not just to cajole others into it.
The condemnation this article mentions does not need to be the sort of political and bodily condemnation that we should remember and repent of. Much of contemporary agreement between Lutherans, Catholics, and others rests on our common priesthood in baptism. But the demand of Baptists and Anabaptists aim to invalidate our baptisms. I know of a congregation that is joint Baptist and Presbyterian and that considers itself to be one church but you join one or the other at the beginning. You can guess where you join if you think it is ok to baptize children. And it gets really dicey when the question of whether those who were baptized as children are "really" Christian like those who undergo so-called "believer's baptism."
This fundamental problem deserves questions and this divergence cannot be marked up to innoculous differences between Christians. The point for which the Lutherans contend is not that only children should be baptized but that both are acceptable. Such a witness it is in this culture to see someone lovingly carried to the font by her Christian parents or other persons who in the innocence of an ordinary Sunday moring are once and for all asked to renounce their old creeds, gods, and commitments for the sake of the God of Israel and his Christ. Some suggest that this idea that we baptize both allows for an option. It really doesn't.
Coming into life of the Triune God is an entrance that is marked in one way by baptism. As to the necessity, the ancient wisdom from the first centuries of Christians, the first age of martyrs (many consider this to be a new age of martyrdom) said that lack of baptism doesn't condemn but despising it does. The necessity, many have since considered, rests in the availability and the timeliness of the baptism. Theologians in the middle ages used the example of the thief of the cross. They argued, perhaps absurdly, that the thief would have been baptized had he lived. But, the situation really didn't make room for baptism.