I don’t know which of the signatories took a different view, or how that’s even relevant. The kol koreh was kind of pareve on the issue of direct melachah, since even grama is normally assur. The kol koreh acknowledges the use of grama devices in hospitals in E.Y., but nevertheless assers the KosherSwitch.
Again, see Shvus Yitzchak (it’s on Otzar Chochmoh, in case you have access) who quotes Rav Moshe, Rav Elyashiv, Rav Chaim Ozer, the Chazon Ish, and even Rav Shlomo Zalman leaning in that direction, that using “grama” devices is actually, al pi din, direct melachah.
This is not merely about comfort level.