You guys need to understand that there are many categories of users who might post something like that in good faith.
First, a lot of Westerners hold anti-Western views—for whatever reason. This leads them to pro-China positions as a matter of tactics—the enemy of my enemy etc.
Second, a lot of Westerners hold anti-US views. That's similar to category 1 but different. We see this from some Canadian, Australian, and European users, and of course even from some American users—again, for whatever reason; people are complicated. This sort of user will also take China's side in a China/US conflict, for reasons of their own that have nothing to do with being Chinese communists.
Third, there are Westerners of Chinese background, either immigrants or children of immigrants, who have pro-China views because they identify with the Chinese dimension of their family history. Sometimes the children of immigrants have more strident views on these things than their parents. Where the parents naturally sought to fit in as immigrants in the West, the next generation tries to balance the two worlds by leaning back towards the country of origin. This group is the most likely to sound like "CCP propaganda" because they have deep knowledge of the culture and usually the language. And of course, if they're first-generation immigrants, their English may not sound native.
Fourth, there are Westerners of non-Chinese background who have spent a lot of time in China, usually for work (less often for travel), who developed pro-Chinese views, or complex/ambivalent views, simply by the natural process of having spent time there. This sort of user often feels like their fellow Westerners have a cartoonish and ignorant view of China, and wants to educate them. Sometimes they 'educate' them by insulting their ignorance, which is unhelpful. These users have native English and can sound like ardent propagandists as well, but actually their motive is to correct what they perceive as a distortion in Western public opinion. Their own views tend to be critical of the CCP, but they dislike what they regard as ignorant anti-Chinese views, and so will argue a pro-China position out of contrarianism. They tend to favor friendly trade and political relations with China, and since the trend of the last few years has been clearly against that, they can come across as rather aggrieved.
Fifth, there are many people who grew up in China, who came to the West for school (or work) and stayed here. Often they are caught between two worlds—having to defend the West and their choice to stay there to their families back home, and at the same time struck painfully by the ignorance, misunderstanding and hostility that they encounter about China here. HN has such users and they are in a difficult position: vastly outnumbered on intense, divisive questions that they happen to have deep personal experience of.
Sometimes these categories also intersect: for example there are Canadian children of Chinese-Canadian immigrants who speak Mandarin and have spent time working at tech companies in China. Their views come from having grown up in a Chinese-Canadian family and having spent time in China itself, and they feel demeaned and even slurred by the generalizations about China that they see on Western internet forums. They show up in the threads with counterarguments, and their counterarguments are often intensely detailed because they have so much personal experience with the topics.
Can you see how complex this situation is? Each of these categories is a minority on HN, but HN is big enough that 'minority' can still mean thousands of people, any of whom may comment in a thread like this—and no doubt there are additional categories that I didn't list (edit: here's another: Westerners with Chinese spouses). Any of these users can post what seem like absurdly pro-CCP comments in a HN thread, for complicated reasons that come from their own life experience. When they do that, other users run into their comments with no idea of the background that would lead someone to post that way, and it creates a shock experience. (For more on the shock experience, see [1] and [2]). Basically, they go 'WTF?' and wonder how anyone could possibly post like this.
Now here comes the pivot in the whole business. When you experience that 'WTF?', you have two choices. First choice, you can say "wow, I wonder how different our experiences must be that you would post what seems to me like such an obviously wrong and evil comment!" That fork leads to curious conversation in which people get to know each other better. Second choice, you can say "You must be a communist party shill! No one would post like this for any other reason! How much are they paying you?" Which percentage of HN users makes the first choice vs. the second choice? Exercise for the reader.
[1] https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...
[2] https://news.ycombinator.com/item?id=23308098