The fact that Xiaohongshu is Chinese is the point, it's a protest against banning Chinese Social Media without holding US-based Social Media to the same standard.

It started from an American user on tik tok saying "we should go to a Chinese app like red book" it's a meme that went wild

I've been saying it, but I think there's also a factor that people simply want somewhere new to go. I can't think of a time when people went back to an older platform while abandoning a newer one.