gvinas akum

Question

rabbi, I recently came accross a article that says that Rabbi Solevaitchik held something interesting about gvinas akum. he held that it was just a din in all the ingrediants being kosher, and since in america all milk is ok, and according toi you, rennet would not be considered edible, and therefor not a problem if if comes from a pig, what is the inyan of gvinas akum nowasdays thank you very much