They care about social harmony.
Don't want to make people upset.
That's the official version.
It's most probably about rejecting the influences from the West, preservation of Chinese culture. Recently there's also quite a huge war on influence of Korean culture.
Just as Fox News won't tell the truth, and hold on to their line even in the face of evidence, so do the Chinese. Most of us are guilty of not trying to be inclusive enough with other people and prefer to live in our little bubble. There is always a cost for that - just look at what happened in 2016-17.
I have no beef in this fight, not being an American, but I see the same behaviour from Fox, CNN (probably the biggest offender), MSNBC, Breitbart and sometimes even BBC.
I don't know, I think it might be more beneficial for those who can accurately observe the political cirque de jour in whatever locale (opposed to being caught up in it) to engage amongst themselves, than trying engage with those who belief systems are dominated by a particular local/flavor (unless such engagement is exploiting another particulars beliefs against another for some gain).
Said another way a bit more reductionist, it seems that any engagement between CNN vs Fox types is rather marginal (for expected outcomes), vs playing both sides and exploiting the cognitive dissonance/norms differential between the two.
I think this chapter in human nature could be described as a conundrum that arises from the allegory of the cave.
That's the official version.
It's most probably about rejecting the influences from the West, preservation of Chinese culture. Recently there's also quite a huge war on influence of Korean culture.