I reached the midpoint of the podcast without seeing a proper argument against this then I gave up.

It tries to argue that higher reward rates are necessary to attrach customers that pay a lot (for credit card companies) and that lower income people are generally subsidized by taxes (obvious but unrelated), but at no point (until where I read) it seems to address the issue of merchants having to generally increase prices due to these cards.

Looking now at that, it does a poor job of making a true refutation.

What that article explains, is that the system of credit card fees and rewards that is used in USA is extraordinarily complicated, variable and obfuscated in comparison with other countries, so it is extremely difficult to discover who gains most and who loses most.

So the conclusion is more like "there is insufficient evidence because we cannot access all the required financial information" for the claims of the other article and the refutation itself presents no evidence that the claims of wealth redistribution are incorrect.