No one's saying that this is going to bring about communism.
People are enjoying that Americans and Chinese are interacting with each other and it's going better than expected, completely shattering the narratives spun by the US state department. Some people are coming to the realization that they've been lied to about China for the first time, on the heels of the US government showing that the sacred first amendment is a lie too.
Saying this is nothing is immaterial too, just doomerism. If 1 in 10 people who switched to Rednote stay there, that's still 1.5 million yankees who now have a direct cultural window into China and will be inoculated against further sinophobic propaganda. If 1 in 100 learn a little Mandarin, that's 150,000 of them. If 1 in 1000 question their beliefs hard enough to become serious leftists, that's 15,000 new comrades.