It's really not a matter whether the Scriptures hold a place of primacy but that the term "prima" has a protestant connotation to it (even argued by a protestant theologian that "sola" should really be "prima"). Just as Matthew (when he challenged the essay) and everybody else has stated, it is simply not found in the Catholic lexicon. However, it is not Hahn's (and company) purpose to bring to the Catholics the protestant belief that the Scriptures is the sole rule to be followed in the economy of salvation, but rather it is because that's how they were bred: as Bible-believers and it is simply natural for them to string along these old "traditions." I tend to think Hahn, Akin, et al., see themselves as neo-reformers, not of the Lutheran mold of course but along the lines of JP-II, as a Catholic reformer. Recall Hahn introducing publicly his five decades of the Rosary, similar to JP-II's "Luminous" mysteries. No lay Catholic of note or of late has dared to publicize private prayers or to tamper with a ancient and revered prayer. We may ourselves have prayers of our own but we have never thought of pushing it to be included in the Catholic book of prayers.
Another thorn in the side is their anti-traditional Catholic stance. I took Akin to task for his insistence of labelling the SSPX "schismatic," when it has already been pointed out (no less than three Cardinals and the pope) that there is no schism. I never got a reply from him. We have also taken note that these converts are amicable to other converts so lomg as they they remain novus ordo. When they don't they are ostracized.