Well, that depends on your interpretation. If you were a Shintoist who did consider the emperor's divinity to be a central tenant, then no, from that perspective, your culture has been eradicated and the current form is a deviation. You're playing fast and loose here with your standards, in any religion, there are various sects which consider themselves to be the true, correct interpretation, and certain others to be false. You yourself thought Shintoists would have to ignore the emperor's renunciation to continue practicing their beliefs. There were Japanese people who saw it that way. And I'm not sure about this but I'm pretty sure you couldn't go around postwar Japan proclaiming the imperialist interpretation of Shinto with the implication of returning to the imperialistic ways, in the same way you couldn't go around waving swastikas in postwar Germany.

The better analogy would be to allow the chinese government to force one person to say “I am not divine”. Let’s say they were able to revive the prophet and make him say these words.

Well, that's interesting, because surely the intent in that case would be to get people to stop practicing Islam. I thought intent was the crucial defining aspect that made mass incarceration not genocide when the US does it but be genocide when China does it.

These standards seem completely incoherent to me. It seems like you're just adopting whatever stance allows you to thread the needle to include the things you want to include and exclude the things you want to exclude.

(Btw, small correction here, but I don't think Muslims consider Mohammad to be personally divine.)