I think I fully understand how Hamachi works now. I've been trying out some old hamachi nfsmw networks posted on youtube. But it seems that though those networks still exist, there are now no people hosting nfsmw game on them. Just like I'm connected to my home wifi network but there are no nfsmw games hosted on it, unless one of the people on the network open up nfsmw and host a server in the lan lobby.
That means somebody needs to start a hamachi network and host a game on it, for testing.
Somebody please do it.