Re: Tiananmen Square in China
"Communism in the Soviet bloc was an unwanted presence imposed by a foreign power, while communism in China was the government chosen, at least in some sense, by the 1940s populace (go study Chinese history if you don’t believe me)."
That's an interesting way to describe it. China's CCP installed itself following a long civil war. The Soviet Union's CPSU installed itself following a long civil war. In both cases, they had plenty of citizens fighting in their armies trying to have them succeed for one reason or another. In both cases, they had plenty of citizens fighting against those armies, hence civil war. Why do you think there's a dramatic difference between those stories? In fact, I'd argue that the difference indicates less support in China's case because there were enough people opposed to the CCP that they set up another country, whereas White Russia did not have enough popular support to maintain any control of land. You chose to compare China with the Soviet block, the largest member of which was the Soviet Union, so your comparison isn't making much sense to me.
"Further, student protests in the 1980s harked back too closely to student radicalism during the Cultural Revolution a generation earlier."
In the sense that they were also students, sure. In any other sense, no, given that the students in the 1960s were killing people following vague instructions from Mao and the students in the 1980s were being killed on instructions from the party.
"To put it another way, while my understanding is that a solid majority of the population of the Soviet bloc wanted their Communist regimes out, this was not true within China in the 1980s,"
Of course, shooting people is a good way to make sure that you don't find out if in fact they did. That was the story after every other unsuccessful protest trying to remove unpopular governments: this did not represent the feelings of the people, because of course nobody but a small fringe group would be stupid enough to want this, right? Everyone else supports us? Which is also related to why you think the CCP has so much approval. Of course China's citizens aren't brainwashed, but many of them are smart enough to recognize that their opinions on the party do not matter and they are not welcome to express them, so if they don't like them, are they going to tell you about it?