Thanks. I am guessing those later theologians, for the most part, are 20th century. I say that because the online Baltimore Catechism I found makes no mention of "in persona Christi" (as far as I know), and so this "in persona" clericalism was unknown among Catholics generally, despite the one sentence in Aquinas, and who knows what he meant really. After Pius XII wrote about "in persona" (Mediator Dei 1947), there was Vatican II, and several of its documents and of course the Catechism are rife with this "in persona." I'm betting that while Vatican II was progressive, nevertheless there was this ugly current of clericalism that was introduced at that time. And now the young traditionalists harp on this "in persona" as if it was something Jesus had envisioned. No, it is just a recent emphasis by Pius XII. Just as infallibility is very recent. Seems like these should be the subjects of a Synod and a thorough housecleaning. Who wants to worship priests? Who needs an infallible pope?