This isn't a history question - but rather a current affairs question the way it's phrased.

Anyway it's not taboo to speak of the cultural revolution in China in most aspects. Xi Jinping has spoken of his time in a cave when his family was purged at a teenager during the Cultural Revolution.

Rather it's impolitic to criticize Mao's actions to a huge extent. The line is that Mao is 70% good, 30% bad actions, and he had good intentions but bad outcomes.

It's not the case. If you talk politely it's generally not taboo. Of course, it depends on who you are speaking to but most modern Chinese living in China are open to talk about it as long as you aren't being disrespectful.

This isn't a question for this subreddit though, as it's dealing with 'now' not 'the past'. There's a 20-year rule.