"Brazier said he expected a trend - if the trade war continues - of businesses moving manufacturing out of China to other Asian countries. "
That is literally what these tariffs are designed to achieve.
The US GDP growth rate is increasing whilst the China GDP growth rate is falling.
This article highlights the US governments concerns perfectly, there is the risk of China becoming the worlds 3rd major market, the US wants the status quo of the US and EU being the only major markets to remain. With 3 major markets there is the risk that 2 of them could gang up against the other.