And had the CBP officer asked for this, I could have produced a number of things indicating this intent.

I try to make it a point to not argue with immigration officers anywhere - it can just get you into nasty problems, but I also like predictability. In many third world countries I've frequented, it's common for officials to make up their own rules with the sole purpose of having you bribe them to get out of it. That isn't what I expect from the US tbh...