You're right, it's not about the AMA. All that has been said is that the AMA isn't going to be one of the organizations that will be handling the testing because they would only want to give the tests to paying members.
It was suggested that the EAA would be one organization to do so, and rightfully so. Flight Test could be another, if they can come up with the capital to buy the required materials. There are other "aviation based" organizations that could also fit the FAA's requirements. The AMA just isn't one of them