And using "culture" as a general concept to dismiss concerns about specific behavior, without actually attempting to posit any particular cultural values, or describe what mechanism actually causes those values to have a determinant effect on behavior, is equivalent to saying nothing at all.
Whatever official party line the current Chinese government espouses, it's plenty clear from even a cursory understanding of Chinese history, from the Warring States period to the warlord-era conflicts of the early 20th century, to the current behavior of the CCP, that China does not have any effective cultural guardrail against factions seeking advantage over opposing factions, which is a phenomenon that has been present in all societies that have ever existed in human history.
Consider that the US was intimately involved with the start of the FOSS movement. Compilers and commercial operating systems are hugely valuable.
Also consider that history the world over is littered with counterexamples. Historical China itself is rife with examples of technological secrecy and exclusivity.
No competent government will voluntarily release (or allow to be released by its subjects) technology that would give them a meaningful advantage on the world stage.
You've made that plenty clear.