Because the relationship with China is more complicated than that. You can see it in the NIH funding research at the Wuhan virology lab or all the made in China goods that the US consumes.
It makes sense for the military to recognize the other forces that pose the biggest threat. But regarding declarations by politicians, it appears to me that internal politics in both countries are driving politicians to make such statements. As in, both American and Chinese leadership see advantage in creating an external enemy. Naturally, as China's power rises, the relationship changes texture, but how much of our attitude change is recognition of the changed situation versus a change in attitude induced by the political class?
It makes sense for the military to recognize the other forces that pose the biggest threat. But regarding declarations by politicians, it appears to me that internal politics in both countries are driving politicians to make such statements. As in, both American and Chinese leadership see advantage in creating an external enemy. Naturally, as China's power rises, the relationship changes texture, but how much of our attitude change is recognition of the changed situation versus a change in attitude induced by the political class?