In short, he argues that Wittgenstein provides no support for the claim that "no statements of fact can ever be or imply statements of absolute value" or for the claim that "all significant judgments are factually descriptive; hence there can be no significant ethical propositions." More generally, Klemke points out that Wittgenstein's arguments rest on a dubious criterion of meaningfulness and on the questionable fact-value dichotomy. These latter are intelligent points.
His paper, however, is book-ended with a very strange vitriol; Wittgenstein, he says, offers no argument. He will not argue that Wittgenstein is wrong--only that he has offered no argument, and his ideas rest on perhaps "outdated" (read: positivistic, I think) assumptions.
One might think that it would be enough to stop there. But here's how he concludes:
I conclude that Wittgenstein's "Lecture on Ethics" is of no worth whatever for ethical inquiry and that the manner of philosophizing which it exhibits is despicable.I wonder whether The Journal of Value Inquiry would let such a paragraph pass editorial review today.
In Wittgenstein's defense, Klemke argues at a couple points that perhaps the only justification for basic claims that Wittgenstein makes is that they are self-evident to him--such as that "all states of affairs are [evaluatively] neutral." But all Klemke says is that this is not self-evident to him; he offers not a single example that would count against what Wittgenstein says. Why isn't that despicable, too? Strange. (What was going on in 1975?)