It's certainly not intentional. It's just something we've never got around to looking into.
If you're interested in exploring gesture recognition in more depth in the Extended.Input library than by all means take it on.
My only question is weather this can be cleanly added to the library without making breaking changes or if we should consider it for the next major version (2.0). In any case, I think the first step is to spend some time trying to figure out how it might fit into the library.