HaLeiVi, very similar, but I’m shifting the “lav davka” from the Ri to the Beraisa, which the meforshim anyhow say is lav davka, because leidosom bikedusha is not nisgayru bonov imo.
It’s worth noting that the Ri’s pshat is mentioned in the Mordechai, Tos. Harosh, S’ma, Tiferes Yisroel, and maybe more. Nobody blinks at the incongruity of the case, and I’ve not seen anyone ask it (I went through the Kovetz Meforshim, but haven’t gotten a chance yet to look at the Mesivta Gemara).
The truth is much more likely to be along the lines we’re suggesting, that the kashya reads too much into the lashon, than finding some esoteric case or application for the din.