Re: Huawei = evil, MediaTek = acceptable
MediaTek = Taiwan, Huawei = China.
Taiwan are US allies, and have similar values to the rest of the "western" world. China:
* are engaged in a trade war with the US
* have very little respect for Western copyright, patents or secrets - especially in their huge domestic market (over time they've gotten better at respecting those in their exports).
* are trying to improve their military capability to allow them to defend against US forces in the region
* have been regularly accused of stealing US military technology
* claim that Taiwan belongs to them, but can't invade Taiwan because there's a big US navy presence there.
* regularly complain because the US regularly sends its warships through the South China Sea, which China claims belongs to China and the US claims is international waters
* regularly complain because the US regularly sends spy planes to fly just outside China's borders, to gather intelligence. These are occasionally harassed by Chinese fighters.
Hence, for the US (and the UK, as US allies), there's a huge difference between the two countries.