IMHO the fact you have Global Entry (which we just obtained but haven't yet used) possibly complicated the issue. We've imported wine at IAD, declared it, and just been waved on because the paper work costs far more than the modest amount of money that would be collected.

It's sounds as if you ran into two cranky officers who were irritated at the thought of the paper work and gave you very bad advice. Everything that was drummed into us about NEXUS/Global Entry ensures that I'll continue to declare everything scrupulously. YMMV.