This is overheated rhetoric.
I can see why you might think that brother, but I really mean it, at least as far as the 20th century is concerned.
If we include the 19th century one could argue that Chuck Finney and the like, or the liberals, did far more damage than Kline.
But I really don't see how, in the context of the 20th and 21st century Presbyterian and Reformed Churches, anyone comes close. There are other folks I would disagree with here and there, like Van Til, but I don't think Van Til significantly undermined gospel ministry. There are others who are more heretical, like Karl Barth, but their influence was primarily on the mainline, not on conservative Reformed churches.
The influence of Kline has been to make it nearly impossible for his followers to apply the wisdom of the Old Testament as it concerns ethics and civil government to our era. The church no longer functions as a light on a hill, because we apparently have nothing to say to or about society. All of that was an "intrusion" or a "covenant of works" and does not apply. We have hidden our light under the bushel.
And then there's the whole "ANE context" thing, where endless passages of the bible actually are not saying what any Christian would have assumed they were saying until circa 1990, because we have failed to grasp the "ANE context" or haven't read the epic of Gilgamesh. The world wasn't created in 6 days, the flood didn't happen... in fact, almost nothing scandalous to the modern, rational man happened.
I'm in the OPC, and every time I hear Kline cited the sermon immediately goes off the rails. Without fail. And there is no one else like that, who is so popular and yet so corrosive. And yes, his followers are a complete disaster.
Now, of course you're free to disagree, and think someone else was worse for the OPC, but that is my genuine belief, not empty rhetoric.
