There are many countries around the world, including Japan, which are quite friendly to the United States. Oddly enough, some are not. Some would like to see us gone, at least as a global influence. Others have stated openly that they wish to destroy us. China is one of those, and has acted consistently with that declaration.
If you are not aware that China is, in fact, our #1 geopolitical and economic threat, you have not been paying attention. (Rather like most Americans were not paying attention to Japan before WWII, and derided thsoe who warned that Japan was a growing threat.)