Bring out the whataboutism.

You only use moral critics and then call me for whataboutism. Let's leave the effect words aside and talk about the data?

understand the need for moderates or right wingers to stan for the USA. The USA and China both have horrendous governments

No, you don't understand, cause you are putting China and US as they are similar, US have 800 military bases around the world, US invaded 2 countries and financed at least 3 coups only in this century, you cannot take it and say lightly "both are bad bru".

I’ve never understood the need for communists to stan for horrible countries

What is an horrible country? This is what I'm pointing, just bad adjectives without any explanations, for a single time you can think about the possibility you are burried by cold war propaganda? Or you deny McCarthyism? China is clearly a better place with the communist party, you have a lot of room for critics but the numbers are astounding. For sure China do things I hate and criticize but I can't understand the need for muricas to call a country that made the biggest leap in combat poverty in the history of humanity, an "horrible country" and refuse to elaborate. Is horrible for who and where?

genocide, war, colonialism, ethnocentrism

Here pls enlight me, I'm totally open to this, but there is any source for what you are saying that does not come from a think tank?
Genocide: how do you have genocide without propaganda? There is any piece of propaganda against any minority in China? You have social media there, how nobody ever got a public speech against a minority in China? I never saw even a Trump/Bolsonaro/Órban/Le Pen like public speech against any minority. If you have, pls link it to me.
War: where is war and what war? After the revolution which war China entered? The last war China participated was the Vietnam war when they defended the already recognized Vietnam government (that even received help from US during the war against Japan) against and US trying to bring Vietnam, Laos and Cambodia back to the French domain. Before it was just civil wars.

Here I will get a comparision, and it is not whataboutism, I have to compare to something that is not just an idealization of myself:

bases around the globe

China have 4 militar bases around the world;
Germany have 4 bases around the world;
Turkey have 10 bases around the world;
UK have 32 bases around the world;
Canada have 4 bases around the world;

If there is countries looking to war, for me seems that China is least one of them. The only thing I remember that is shit right now is the Indonesia x China situation, but is far away of escalation.

concentrate tremendous power at the top

How much it is? I'm not saying that China is a beautiful place, but there is actual voting systems with a enourmous rotation of ppl in the congress and officially the general secretary have less power than a president in presidentialism and similar to a a Prime Minister.

Also about power, 1,095 strikes recorded in 2021, for me strikes are a great indicator that workers have some kind of power and can demand better conditions.

I’ve never understood the need for communists to stan for horrible countries

Answering your question, do you never thought the possibility that these "horrible countries" were not that horrible places and that you (specially if you are on US) have a completely distorted vision of these countries because you are historically in war with them? And again, China is not a perfect place, but no country is, countries don't come from nothing. But if you still try to label things without any deeper insight, like bad, good, genocide, war, you will never understand, for sure.