The US government allows China to export cheap, relatively low-tech goods to the US. However, it's clear now that the US government will ban any Chinese high-tech company that gains significant market share in the US. In some cases, such as ZTE and Huawei, it will go much further and attempt to put them out of business altogether, using sanctions and threats (e.g., threatening to end intelligence sharing with the UK unless it stops getting Huawei equipment).