I don't think this is a case of dog-whistling, because AFAICT the author isn't trying to conceal his point.
I.e., he intends every reader to recognize that he's saying that the publisher might be biased. He's not being explicit about what that bias is, but presumably he expects curious readers to look into it themselves.
I.e., he intends every reader to recognize that he's saying that the publisher might be biased. He's not being explicit about what that bias is, but presumably he expects curious readers to look into it themselves.