Timothy Gorringe, in his study Karl Barth: Against Hegemony (Oxford, 1999) helps us understand why the Swiss dogmatician was so resolute on this score. Essentially, as Gorringe reads him, Barth equates worldview with ideology, and theology must be bound only to the Word of God and not to any distorting human intellectual constructs. This does not mean, though, that that the issue is preserving theology per se from the fray of human conflicts and controversies; rather, the question is: Does theological ratiocination bind or loose believers for the concrete struggles of social and political life.
Barth has rightly been described [by Clifford Green] as a "theologian of freedom". From one point of view the Church Dogmatics is a gigantic exploration of the meaning, presuppositions, and actualizations of human freedom. The negative, critical, mode of this exploration is the attack on hegemony, on world views which take over the freedom of the gospel. Further, to a very significant extent Barth believes that God frees us by liberating us from hegemony (p. 3).
Gorringe reads the thrust of Barth's theology, on the whole, as positive: The God of love and freedom emancipates human beings from bondage to sin and falsehood through Jesus Christ, thereby empowering them to enjoy communities of freedom and mutuality. Nonetheless, as Barth often pointed out, a "No" is encompassed within the overarching "Yes" of God to humanity in Christ. Much of the negative work in theology takes the form of ideology critique.
The foregoing point dovetails with how Gorringe (compellingly, it seems to me) interprets Barth's obsession with revelation, especially in the early years of his theological project, not as an enmeshment in the post-Enlightenment crisis in religious epistemology but, rather, as integral to the project of human liberation. He reads the trope of revelation as an arch that unites the Church Dogmatics from the doctrine of the Word of God to the explication of the role of Christ as true prophet within the doctrine of reconciliation. Gorringe writes:
The centrality of revelation in Barth's thought, not just in his early work, or in the first two volumes of the Dogmatics [meaning 1/1 and 1/2] but also in IV/3, means that the negative attack is also positive liberation. How do human beings take up their vocation of freedom? An important part of Barth's answer is: Through the saving knowledge of Jesus Christ. But this means the issue of ideology is inescapable, and it does in fact recur again and again in the Dogmatics in the form of the attack on world views.
As Gorringe reads it, this aspect of Barth's thought is meant not to lead to aloofness from the realms of society and politics but, rather, is to serve as a catalyst for speaking truth to power and for mobilizing change. This stance against worldviews or ideologies colonizing theology was contextual and, thus, took different forms throughout Barth's career: In a context still in the throes of Harnackian liberal theology, Barth's protest took the form of a radical critique of religion. Later he attempted to confront the demonic ideology of Nazism with a resolute affirmation of the freedom of evangelical preaching and with a radically re-imagined doctrine of God. Finally, in the post-war period, Barth refused to enable the hysteria of western anti-Communism, offering as a counterpoint joyous treatises on the reconciliation of all people with God and each other in Jesus Christ.