Qecause organics are too hard to control so synthetic servants would be easier as they work off "logic".
So they can advance further, if they took everything whole sale there's no way to be sure that the next time around thered be technology better then what they have. Giving them hints of previous work allows for progress. Its like if I gave you a xbox 360 you'd try to find a way to progress on that rather than expecting you to make the 720(or whatever microsort makes next) by yourself.
C, seriously, if you only knew what you were missing by not seeing Die Hard, you wouldn't even be on the site right now, you'd be running out to watch it. You can buy the Blu-Ray used off Amazon for under $7.00. I wouldn't bother bugging you about it if I didn't think it was worth your time. Trust me, SEE THIS MOVIE.