The case is ongoing and appears to (IANAL!) rest on American ranchers refusing to be commercially compelled to pay for speech they oppose, namely advertising that fails to differentiate the American sourced product from that of Canadian and Mexican competitors.
So a First Amendent assertion set against an Eighth Amendment reposte, namely that as Congress has enacted specific check off advertising legislation then the advertising concerned is Government Speech that trumps commercial rights.
There is clearly a live VRM conflict occurring, resulting in the above case, so I'm wondering how what is happening might help to develop effective VRM