Board Thread:General Discussion/@comment-26198769-20150313212242/@comment-26205636-20150319041147

Atmosphere is the only thing that would make Earth value in the eyes of a Gem since Space is infinite ocean of rocky debris, comets, asteroids, moons and uninhabited planets that would provide easier targets for conversion than Earth without sacrificing the lives of any possible inhabitants (this form of conversion would probably be acceptable to the Crystal gems since no one is hurt). However if you look at the effects of the Kindergarden, the gem machine seem to pull the life out of the land around it and uses it to make more Gems. This process would probably result in not only more diverse gems but a greater numbers, higher quality gems and be seen as a much more efficient process but at the expense of the native lifeforms. However based on Peridot's attitude (who is probably one of the most neutral characters in the show) toward Steven, Most gems care little organic even intelligent life which may viewed as being primitive and worth less than dirt when compare to Gem. Akin to giving a sick baby an antibiotic at the expense of billions of bacteria.

Jasper's attitude toward fusion (Attitude possibly shared by the greater gem society) can also be explained this way as well. Fusion weakens the race by decrease their numbers potentially making it harder conquer other planets necessary to make a greater number of gems. It is also inefficient because two weak gems fusing to make one average strength gem decreases the underclass workforce needed to produce hundreds of gems of similar strength. Also stronger fusion gems can potential alter the power structure within Gem society destabilizing it. In such a society, even a fusion resulting from a loving bond can been seen as a self action reserved for the lowest levels of gem society who could cut it with their own strength.

Finally, Gem Society was technologically advanced 6000 years but probably not much since civilizations stagnate as they age. It was capable of building interplantary FTL space ships and pocket dimensions. While alot of innovation may have occured since then, what probably scared Lapis Lazuli was the fact that much of tech was devoted to attacking and controlling other gems (so gem version of 1984). A successful rebellion by Rose Quartz would have sent ripples through the homeworld's ruling class who not want history to repeat itself unintentionally leading to a more dystopian society on the Home world.