It's only "conspiracy theory nonsense" if one is completely unfamiliar with how gaining access to the Chinese market works. I've been involved in more than one of these kinds of operations. These companies' primary goals when dealing with American companies (and, I'm guessing, any foreign company) are: 1) acquire IP so that China can control it; 2) acquire data on users, especially Chinese citizen users, but in general all the users. The notion of "competition" in the sense you imply is at best a distant second consideration. These companies can and will subvert what a typical Western capitalist would view as their own interests in service to that, because otherwise the CCP can and will destroy them.
it's conspiracy theory nonsense I'm afraid