In practice, China is highly capitalistic as an economy. It's authoritarian capitalism, not communism, even though it has a "communist party".
This phenomenon of bikes piling up is literally venture capitalists throwing money at startups (in return for equity) to deploy more and more bikes to outnumber competitors in a hopeless race to monopolize bike sharing. It's literally an exhibit of one of the failure modes of extreme capitalism.
Giving them away, as GGGP suggests, would actually be a departure from capitalism, and perhaps a good one.