Because unless I know different from an authoritative source, US
Customs pretty much considers anything much above a transistor to be
military dual-use tech in the post 9/11 era. Take a look at the Ebay
ads these days... you'll hardly ever see a US Ebay willing to sell
outside CONUS due to export hassles.

Importing is almost as bad... Outside of NAFTA or CAFTA expect pay to
duties in excess of 12 to 50 percent above your $400 annual exemption
for gift items.

The Eternal Squire