Disrupting the Buld/Buy tradeoff
These shortsighted policies might appear to slow down China in the short term but what they're really doing is altering the build/buy tradeoff. Forcing the Chinese to do work that was not cost effective for them might slow them down in the near term but it won't stop them, we'll just end up with even more formidable competition as their versions of technology, unencumbered by years of development compromises, becomes the better mousetrap.
Obviously we can continue telling ourselves that they just can't do what we can do. All the time buying products from Taiwan, Korea and Japan.
We're also causing our 'allies' significant economic hardship by insisting on them enforcing our sanctions policies even if it hurts them. (Put simply, we make hay while you freeze. Thanks!)