issur gavra/cheftza: Brisk vs. R' Shimon's derech

Awhile back I did a post that drew a contrast between R’ Shimon Shkop’s style and that of R’ Chaim. Briskers are interested in structure as an end in itself; R’ Shimon is always looking for a “why” that is hiding behind the scenes. Brisk is gavra/cheftza; Telz and R’ Shimon is all about sibah/siman and finding the true “goreim” of the din. The first sugya in Nedarim jumps out as an example of the difference in approach. Every Brisker jumps for joy when he reads the gemara’s distinction between nedarim, which are issurei chefzta, and shevuos, which are issurei gavra. But R’ Shimon is not satisfied. The Rishonim say (I did not double check, but IIRC this is a Ritva) all issurei Torah are issurei gavra. R’ Shimon (Shiur #1 on Nedarim) asks: if an issur cheftza means the object is somehow spiritually “tainted” in some way, why should the issur of neveilah or cheilev not also be categorized as issurei chefzta in the same way a neder is? What is it about neder that distinguishes it from other cases? I don’t think a Brisker would ever ask such a question, nor to the best of my knowledge does Brisk ever formulate an answer. A Brisker just accepts the distinction as an a priori part of halacha: in some cases the focus is on excluding objects from use, in other cases it is on human behavior, but why and where the focus is placed on one of the other is of no concern to us.

R’ Shimon takes the Brisker world of gavra/cheftza and transforms it into the sibah/siman world of Telz. Cheilev or neveilah are simanim that the ratzon Hashem has declared these products off-limits. The issurim themselves are the products of Hashem’s plan for perfecting us (i.e. ratzon Hashem is the goreim,not the anything inherent in the object itself). The issur of a neder is not the product of G-d’s will; the issur is its own sibah and motivation, it is an end in itself which start and stops with the object at hand.