Apparently these 'experts' were unfamiliar with not only passages such as the Sermon on the Mount and Romans 12, but the testimony from Church History. There have been many groups which have opposed the use of violence and especially the misnamed Christian Just War Tradition. Most of the groups rooted their opposing arguments in Scripture. To dismiss them as liberals who didn't take the Bible seriously is a travesty.
I couldn't decide if they were grossly misinformed or just being slanderous. Once again it's interesting to note that the Peace Tradition of the Waldensians, Anabaptists, Quakers and others is hated above all by the Constantinian mindset. These days it's better to be a Roman Catholic than to dare and reject the Constantinian/Dominionist order.
There is indeed a pacifist strain in the Theological Liberal tradition, but in that case it's based in part on a rejection of Scripture and the assumption of extra-Biblical philosophical principles and values.
These Non-believers (for that is what they are) would accept the words of Jesus in the Sermon on the Mount but then believing the rest of Scripture from the Old Testament to Paul contradict his message, they also reject the greater Scriptural authority. They do not believe the Bible to be Divinely Inspired, and in the end the words of Christ are the theological equivalent of the sayings of the Buddha, Gandhi or Martin Luther King.
The Old Testament and Paul do not contradict Christ. All of these passages must be understood in their context. One of the keys is to understand the Bible in terms of Redemptive History rather than restrict it to systematic theology. Trying to force Scripture into a logically coherent framework and system of ethics is a sure path to distortion.
In the present context of the New Testament, of the Last Days, we are called to leave vengeance in the hands of the coming Christ. In earthly terms, the powers that be are ordained by God but not sanctioned by Him. They exercise the sword of vengeance, not to glorify Him to be sure... but nevertheless serve the greater purpose of providing stability and a semblance of order. The state, even civilization is a means, not an end and the cultures of the world and certainly their political manifestations will burn up at the Parousia.
In a previous generation it was the Fundamentalists, men such as William Jennings Bryan who stood for peace and it was Progressivist Theological Liberals who believed in the morality and necessity of war. World War II brought about many changes, not just on the map, but in how people thought through these questions. In fact it was the Liberal Niebuhr who after World War II so eviscerated the Mennonites with his arguments, that not a few of them were led to abandon their pacifist position. No pacifism was possible in the new era. Sadly had they not also lost their way with regard to the Scripture they could have easily answered his arguments. To Niebuhr the words of Christ and the message of the Gospel were quaint but not realistically applicable to modern life. Niebuhr was not a Christian (as far as Scripture is concerned) and approached these issues as a worldling.
The truth is as titanic as World War II was, in reality it did not change the fundamental questions that have existed since Adam's Fall. We were told there would be wars and rumours of wars. In fact if we're thinking as Christians we would also be free from many of the myths and false interpretations of the war and we would rightly understand it for what it was... evil versus greater evil. The Nazis did not represent anything that had not already been present. Racist thieving murderers they were, but to many non-Europeans the British, French, Portuguese, or Belgians were little different.
The only difference with the Nazis was their aggressiveness and the theatre they chose to exercise it in... Europe as opposed to Africa or Asia. The setting also interacted rather badly with the new technology, in particular the airplane. The colonizing empires had not had to employ such brutal methods. The British were also responsible for millions of deaths but could convince themselves that they were not culpable because they had not overtly planned them... even though they created the conditions and then when famines erupted, though they had the means, did nothing to alleviate the situation. That's little different from what Stalin did in the Ukraine. The Nazis were, I supposed it could be said, honest about who they were and what they were about.
All of this is to say that we need to be wary of radio experts who are more likely to give pat answers and provide little more than soundbite theology.
Five minute Bible Studies and quick theology lessons only lead to distortion and the dishonouring of God. These are weighty matters which our modern frenetic methods of communication cannot deal with. If you want to get serious about Scripture and Doctrine, don't look for much help from Pop Christian culture and never think that a mobile phone programme can in any way help you learn the ways of the Kingdom. There are no quick and easy answers to any of these questions. Our modern methods are inadequate to deal with anything weighty. The radio programmes that are of any worth will be boring for the modern listener and likely a great deal less than popular.