Should they be soft?

The sole of almost all animals hoofs (like horses, donkeys, cows, etc) are all softer than the outer shell. You can par away some of the softer area so that it is flat and the goat has a level surface to walk on, but yes, they aren't actually rock hard on the entire hoof!

They should feel kind of rubbery, like an old bias ply tire.

Not a stupid question at all.

With newborns yes very normal to be soft, it hasn't grown and isn't dry. It is a fresh hoof.

For adults, if they haven't been trimmed, they can be very hard, there shouldn't be any give when you push on it, they grow out and are dry.
With some, they are very hard to get started with trimming, because they are so dry.
When it is rainy, the hooves soften from being wet(damp), but shouldn't be easy to push on the sole, but will be easier to trim, if it has been rainy for a few days, they are forced to walk in wetter conditions, which softens the hooves.

When freshly trimmed, it will be a softer hoof, when you push on it, very normal. It is new, fresh exposed hoof, not dry.
If they are subjected to walk on a rocky or rough terrain, some may get stone bruising, because the hoof is softer after a rain or a trim.