The middle of Taiwan Strait is public/open sea so it's OK any ships from any country can go through, why China is so sensitive about this? Also China warships often go through 'GongGu Strait' (between Japan Islands) and it's OK for Japan. China seems to treat Taiwan Strait as his 'internal sea' which not make sense and illegal, and also make troubles for himself (since China can not attach the warships in Taiwan Strait), the same way as you call everyone passing your home 'TiaoXin' but you can not do anything, so it only make you look bad and stupid.
The US and its western allies are calling China’s bluff. With increased economic and military power, China wants to make territorial and maritime claims in South China Sea and soon in other places, if its aggression is not stopped. The US, now joined by Canada, Japan, Australia and the UK is the world’s peacekeeper. The WWII has taught us a lesson that appeasement toward Fascist could only lead to war and greater casualties later. Aggressor must be confronted head on.