Yes. They're not OK with large scale public discourse about it because Western countries have been producing fabrications as propaganda for decades now and engaging in discourse of it would require dealing with an overwhelming international media machine. For the Chinese government, it's a smarter strategy to say we won't discuss it because it's just too controversial. The truth is available for people who want to review the historical record in earnest. China is under no obligation to combat the West's propaganda on each and every topic