Because they're fucking evil.

Because they want to lead the NWO.

It's the same reason the US wanted a forward deployed Navy since near our founding... Commerce. The security of sea routes especially with their Belt and Road initiative will need it to provide security and safe haven.

With Biden in power they can expand and prosper because the sanctions and push back have ended. This is a next logical step for them and could make the american homeland reachable by attack or influence/holding actions, on a steady basis not just one time events, which will be a first for us.