Hong Kong has just been a transshipment point for stuff coming from Shenzhen so Chinese could claim "ships from HK" or try to avoid customs, and make it easier to get into the US. You can't just ship everything to HK first because it's not allowed. So they will ship 50 cases of goods to HK, maybe half of them get caught and the rest gets through. Even if only 5% gets through, they make enough profit to not care about the other ones that are confiscated.

It's a good move to get rid of that special status when it's just being used as a loophole.