From what I understand, this interpretation relies on the wording in the new law which prohibits transactions funding "illegal" internet gambling. Because only certain states have expressly made online gambling illegal and not the Federal Government (which has still not amended the 1961 Wire Act), some casinos have limited their player bans to those states.
This seems to me to be the most likely rationale for the *prohibited states* policy we're seeing evolve at the moment at those casinos and poker rooms that have decided against an all out US player ban.