Let's pretend that there are a small number of customers that Buick loses because of manufacturing in China. Those customers are people who would buy the Envision, but are also astutely aware and passionate about domestic manufacturing and globalization. So much so, that the Chinese manufacturing of the Envision is enough to steer them away from the vehicle, even though they like it better than everything else. OK, so these are the people that Buick has lost as customers.
At the same time, Buick chose to manufacture the Envision in China because it was cost efficient. That allows them to price the vehicle lower, and also to have a higher profit margin. Manufacturing in the US (or some other non-China place) would likely make the price of the vehicle rise and also eat into profit margins.
If moving manufacturing might prevent Buick from losing the small number of customers I outlined at the beginning of this post, that benefit would not be greater than the loss of profit and the number of buyers who are priced out of the market due to moving manufacturing outside of China.