Closed source control is scary in general but people only care when it's China.

Sometimes governments aren't completely stupid and realize having your communication network ran by foreign companies beholden to a sort-of enemy country is probably a bad idea. Huawei phones don't matter, but they make a lot of stuff used by telecom networks that a consumer doesn't see, which is the far bigger deal.

This is why China is correct to ban American social media who let the government do whatever they want with that info. Also why national security people are probably right to not be dependent on China for something as critical as telecom network hardware so that they have less to think about when wanting to start a war.