Here's a wild and crazy theory: Is it possible that the VW list you looked at isn't complete?There are literally hundreds of oils that have approval from VW for the 507 spec. Mobil has four oils with VW 507 approval. I don't see any amsoil products on the official approved oils list. My guess is that they could get approval if they were willing to pay for the certification.
Is it possible it was published before Amsoil was approved?
Have you ASKED Volkswagen?
Or is it just more comforting to believe that voices come out of burning bushes and that Amsoil is the work of the devil?
Seriously. It's approved. There was no second shooter on the grassy knoll. Armstrong DID walk on the moon.