Yeah, in support of your thoughts: I can state, from first-hand experience as a former AT&T pay as you go customer, their store staff have absolutely no issue telling you they don't/won't/can't support you - so I can't see why AT&T couldn't do that with smartphone users that don't want data.
However I don't blame the GP, he is stuck in the role of explaining his employer's official position. I've had to toe that line myself a few times. I'm not very good at it, unfortunately (I love to shoot my mouth off) - but when you don't toe the company line with your end users, things can get uncomfortable rather quickly.
As a side note - AT&T also requires a data plan for their pay as you go smartphone customers, even if the customer doesn't use data. They used to offer some very low cost data plans you could use alongside a 10 cents a minute phone plan, at least; but now they're forcing people into a minimum expenditure of $30/month (required smartphone+text is $25, IIRC; and they require at least their lowest data plan of $5). So I switched to T-Mobile, who has a $30/month plan that's actually a great deal for people who basically just use text and data but hardly make phone calls (on AT&T I stuck mostly to wi-fi networks, but with T-Mobile I don't bother - but I still use less than a gigabyte a month).
As a second side note - although their advertising targets older individuals, Consumer Cellular is an AT&T MVNO with some very attractive, low cost plans for people like the guy in this story. I'm considering switching my wife's phone to them - she "really wants an iPhone", but hardly ever texts, uses almost no data, and doesn't make many phone calls.