My understanding is that Chinese EVs aren’t technically banned in the US. Rather, they have (and have long had) extremely steep tariffs, making them non-competitive.

They probably still need to complete things like crash testing and emissions certification. These become a requirement after imports hit a certain number.

My guess is that Google hasn’t imported enough of them to reach that threshold yet.

In order for a law to be effective, it must be enforced. It’s simply just not being enforced, for Google.