Route like '/users/' will catch all requests on '/users/*', so you can fix your problem by changing the order of routes:
_route = [
RedirectRoute('/', 'home.HomeHandler', name='home', strict_slash=True),
RedirectRoute('/users/comments/new/', 'users.UserNewCommentHandler', name='new-comment', strict_slash=True)
RedirectRoute('/users/<usercode>', 'users.UserSingleHandler', name='user-page', strict_slash=True),
]