Yeah, being clear, when they first go into the game, they don't even know what the point is, so, the aim is to find out what the point is. This isn't really unusual in a game; FF7 takes until you leave Midgar before you find out what your real aim for the game is, and even then there's a bunch of facts still to be revealed, as an example.

Which also makes John's reaction (at first) anyway reasonable enough, he doesn't know anyone else is dead. To the best of his knowledge, they're not and he's in this whacky adventure. Ditto Rose, although lesso Dave. Jade also doesn't know earth is destroyed, although they do know its in trouble.