Space Jockeys aren't albino humans, they are their own lovecraftian type bio mechanical species. They have to fuse their bodies with their technology to make it work.(bio-punk) Everything about them as a species is grotesque(think the video game scorn). Xenomorphs aren't "the ultimate weapon" just a predator lifeform they were working one. They got cocky as they wanted to make it more deadly when they eventually lost control and the research lab where they were created was wiped out. Its ambiguous whether or not space jockeys are extinct or not. It hinted that xenos didn't wipe out them but rather something else did (which makes whatever did much scarier)