So reasons include: politics (Lots of swing voters work in the auto manufacturing industry that would get pissed with an influx of chinese cars), national security (worries of the type of information Chinese cars would send back home), and lastly industry protectionism.
As much as this sucks, I kind of agree. We really don't want to rely on China until they prove to reliably not want to screw us. If this was Taiwan, Mexico, any country from the EU, etc. I would definitely want their cheap EVs to hit our market and bloody up the american manufacturers.