Geisler is a culture warrior in the worst sense. He’s one of the framers of the Chicago Statement on Biblical Inerrancy (and the follow-up statement on hermeneutics, which demands a literal interpretation of Genesis), and he goes after anyone and everyone he thinks is compromising absolute truth or the inerrancy of the Bible, as he defines both. For example, a review of his recent book, Vital Issues in the Inerrancy Debate, lists the following people as violating the Chicago standards:
Ben Meyer, Birger Gerhadsson, Bruce Waltke, Carlos Bovell, Charles Talbert,Christopher Ansberry, Christopher Hays, Christian Smith, Clark Pinnock, Craig Blomberg, Craig Evans, Craig Keener, D. Brent Sandy, Daniel P. Fuller, Daniel Harlow, Daniel Wallace, Darrell Bock, David Capes, David E. Garland, Donald Hagner, Donald K. McKim, Douglas Moo, Edwin Yamauchi, E. P. Sanders, Ernst Wendland, Gary R. Habermas, George Eldon Ladd, Gerd Theissen, Grant R. Osborne, Gregory A. Boyd, H. C. Kee, Heath Thomas, I. Howard Marshall, J. Merrick, J. P. Holding, Jack B. Rogers, James Barr, James Bruckner, James Charlesworth, James Crossley, James D. G. Dunn, Jeremy Evans, James Hamilton, Joel N. Lohr, Joel Watts, John Byron, John R. Franke, John Schneider, John H.Walton, Justin Taylor, KenSchenck, Kenton Sparks, Kevin J. Vanhoozer, Lee McDonald, Leith Anderson, Leon Morris, Martin Soskice, Matthew Montonini, Michael F. Bird, Michael Green, Michael R. Licona, Moises Silva, Murray Harris, N.T. Wright, Nick Peters, Nijya Gupta, Paul Copan, Paul Jewett, Peter E. Enns, Paul Ricouer, Peter H. Davids, Phillip Long, Richard Burridge, Richard Horsley, Robert H. Gundry, Robert W. Yarborough, Robert Webb,Scot McKnight, Stephen M. Garrett, Thomas Schreiner, Tremper Longman III,W. David Beck, Walter Liefield, William Lane Craig, William Warren, and William Webb.
So, by Geisler’s standards, he may be the only faithful teacher left in the church. The problem with his approach is precisely its absolutism. As the list above makes clear, he is certain that he is in possession of the absolute truth and is ready to throw out everyone who is in error in even the slightest detail.
On Thiselton, his book on hermeneutics, The Two Horizons, specifically references the work of Heidegger, Bultmann, Gadamer, and Wittgenstein, and regardless of the specific use that Thiselton makes of their ideas, the simple fact that he interacts with contemporary philosophy is enough for Geisler to write it all off as “relativism.”
Frame, likewise, has been accused of relativism, but it is mostly based on the fact that he uses “existential” as one of the categories of his Christian ethics: normative, situational, and existential. Vern Poythress, a former student of Frame’s, explains it thus:
"Human knowledge arises in the context of human finiteness. Any particular human being always knows and experiences truth from the standpoint of who he is.2 He has a perspective. He can learn from others by listening sympathetically to what they understand from their differing backgrounds or perspectives. The diversity of human beings leads to a diversity in perspectives. John Frame affirms both the limitations of any finite human perspective and the absoluteness of God’s knowledge. "It [perspectivalism] presupposes absolutism [the absoluteness of God’s viewpoint]."3 The presence of God implies that truth is accessible to human beings, and that there is a difference between truth and falsehood. In this way, Frame is an “absolutist” rather than a relativist. But he invites us to take seriously the insights and the differences in emphasis that arise from viewing a particular subject-matter from more than one point of view.
"Besides showing a wider interest in diverse human perspectives,4 Frame introduces the use of perspectival triads, and affirms their relation to the Trinitarian character of God.5 Frame uses primarily two triads. To discuss God’s Lordship, he uses the triad of authority, control, and presence. As Lord, God has authority over us, exerts control over us, and is present to us. Each of these three aspects of God’s Lordship can serve as a perspective on who God is and how he relates to us. These three perspectives are involved in one another, and each helps to define and deepen our understanding of the other two. All three aspects of Lordship are involved is all God’s relations to his creatures.6
"To discuss ethics, Frame uses another triad of perspectives, namely the normative, situational, and existential perspectives.7 The normative perspective focuses on the norms, God’s law and his expressions of his ethical standards for human beings. The situational perspective focuses on the situation in which a human being must act, and endeavors to discern what attitudes and actions promote the glory of God within that situation. The existential perspective focuses on persons and their motives, particularly the central motive of love. Again, these three are involved in one another. God’s norms tell us to pay attention to the situation–in particular, the needs of others around us. The norms also tell us to pay attention to our attitudes (existential). Similarly, the situation pushes us to pay attention to the norms, because God is the most important persons in our situation, and what he desires matters supremely. The situation also pushes us to pay attention to the persons in the situation. Our own attitudes must be inspected for their potential to change the situation for good or ill.
Because God is Lord of all, these perspectives harmonize in principle. God promulgates the norms; God controls the situation; God created the human persons in his image. But in a fallen situation of sin, human beings have distortions in their ethical knowledge, and the use of one perspective can help in straightening out distortions that people have introduced in the context of another perspective."
Here is the article quoted above.
Here is Frame’s own A Primer on Perspectivalism