From their perspective it's more like a mass recall.

There still is the possibility that the Rose Quartzs were a brand new type of gem at that time, and they feared that they were easily rebellious by nature, as each gem type has common characteristics. Every other rebel gem we've seen in the show, especially among the Crystal Gems, seemed to be pretty loyal to the Diamond Authority by default, until they met either Rose or Steven. And we don't know any Rose Quartz except for the earthlings.