The "reference" to Rand's sister made a point--namely, a lot of choices can overwhelm people, especially when they're used to no choice. They may not like it. Noonan is not, in that paragraph, aiming to "dismiss" or "support" private accounts. She's writing about how people will react to them.
In PN's world, everything is so overwhelming for ordinary people. It's in complete conformity with her little garden column last summer.
However, since those who are nearing retirement (over 56) will not be affected, whether they enjoy making choices or not is irrelevant. A better musing would be whether younger voters want responsibility.