Americans have no reason to care what happened in Tiananmen Square. That’s Chinese domestic politics. But whether Iraq actually had WMDs does affect Americans, as the people who financed that war based on the failures of the U.S. government.
Foreign propaganda is much less dangerous than domestic propaganda because domestic propaganda is more likely to relate to issues that actually matter to citizens.
> Americans have no reason to care what happened in Tiananmen Square.
It's not about what you care or don't care. It's about using China's social media service to discuss the very topics that China wants to censor. Again, go to TikTok or whatever alternative service provided by China and try to refer to the Tiananmen massacre or Uighur genocide. See what your paragons of free speech treat that.