Can you imagine hundreds of journalists who would lie to promote a false story that hasn't really been all that effective and harming China (the only possible motivation for such a campaign). And not a single one of the journalists approached by the creators of this campaign leaked anything. If this really was a massive conspiracy theory, that itself is a much much bigger story than the Chinese rounding up people that most of the world don't seem to care about. One of those hundreds of journalists wouldn't have been able to resist such a scoop.

I'm guessing the next part of your conspiracy theory is that the conspiracy group is so powerful that everyone is scared to come forward. But if they are that powerful, why construct such an ineffective anti-china story? Surely such a powerful group could construct something more damaging.

Sure. I can also much more easily imagine pseudnonymous accounts making material misrepresentations for politically motivated reasons, spreading FUD about journalists making things up.