At one time, military technology from the US was never sold with the basic weapon system if there was a potential for it to be re-distributed. Thus, ships were sold without the fire control, communication, radar, and sonar systems, as well were planes and tanks. It really all came to a boil when Hughs (remember ole howard hughs?) Corporation, which at one time manufactured all the defense related radar systems, including guided missiles in the US, actually was caught selling its technology to one nation which was going to pass it to another less acceptable nation.
Personally, I don't think we should be supplying anyone but ourselves. Then again, it like the previous post stated: are we doing this deliberately in order to promulgate better technology?. I would say yes, its deliberate.