They are provoking Japan. They are poking India. They are trying to spread influence down to the Philippines and out to Africa. They are trying to build a blue water navy.
This is what weakness brings, especially when Communists are involved. American politicians of all stripes have been downplaying the ideological aspect of China for several decades, and focusing on the trade and industrial aspects, but...we should never forget:
They are Chicoms. Chinese. Communists.
The really interesting part is that this being mountain warfare there won’t be a lot of hi-tech stuff being used. It’s the old-style PLA going nose-to-nose with the local Indian units with light infantry weapons, mortars & pack-howitzers. Nothing fancy. It will be short, sharp & bloody and India will probably have to decide on whether to escalate.