You should have thanked him and asked for your baggage tag not to get the priority treatment. IME when baggage handlers see priority that just means chuck it harder! Also, in the past several months I've had a UA Gold and checked bags, I haven't noticed a difference on the bag coming out first. Keep in mind many travellers can get this benefit through Premier Access a $10-$20 add-on for many flights which also includes priority boarding
Often times I've see non-priority bags come out first (especially arriving in YYZ & YOW). This is arguably the least useful *A benefit imaginable and hardly worth any argument.
Safe Travels,
James