China needs to keep young men employed to reduce the probability of riots and revolts. Unlike the US's private sector, China's private sector is incapable of employing enough young men, so the government employs many of them in building roads, rail lines, dams, bridges, cities, etc.

I'm not particularly impressed, especially when I see video of new cities with almost nobody living in them.

Oh, this one's easy. The PRC is openly critical of Israel which has resulted in them being socially blacklisted by western society. After all, we make that kind of speech expressly illegal in our legislation: https://en.wikipedia.org/wiki/Anti-BDS_laws