Hare doesn't care much about mathematical purity, and the features it does have were chosen on the basis of what is useful in systems programming.

There are sum types (tagged unions), but product types (tuples) were a late addition and we still don't have support for tuple unpacking or pattern matching on them.

Tuple unpacking is something that's been put off for very long but looks like it is going to finally happen soon. Pattern matching on types other than tagged unions hasn't been completely ruled out yet, but is also not guaranteed to happen.