User blog comment:USS Enterprise CVN-65/The New (And Improved) Official Roleplay Room/@comment-10905876-20150423230355/@comment-10905876-20150427201135

Actually, it's realy more the droids who call humans, and other sith, meatbags. It's referencing HK-47 from the KOTOR games. Here's an explanation of the terms origin from HK-47 himself: