The problem of Hoppe in this case is bad education (Habermas). Almost all opponents of Popper (Feyerabend, Kuhn, Habermas) seem to share the same error - a simple replacement of verification by falsification, but everything else remains as in positivism. The number of people who understand that falsification is also only hypothetical, and not certain, or that it is not a particular statement, but a whole theory, even combinations of different theories, which have to give falsifiable predictions, seems minimal.
If one reads Mises, there are a few reasonable points about the difference between natural sciences and economics. In fact, we know from ourself how human society works - there are individuals with particular interests, and they try to realize them. Such things we don't know about atoms or quarks. So there is indeed a difference. And, of course, also the other one that our theories, if known, are able to change the game itself. That's also impossible for quarks.
But from a fundamental point of view it doesn't change much. So I agree with Popper that there is a unique scientific method, even if there are large gradual differences.
Given that the Austrians have not understood Popper, so that they are arguing, in fact, against variants of classical positivism, they are in some sense right: Theories cannot be derived from experience. One needs something a priori. Now they make the Kantian error - a priori, means, not based on experience, means, it needs an independent justification, some sort of laws of thinking.