But Chemistry cares about actual chemicals and Astronomy cares about our actual universe. Likewise, Computer Science is overwhelmingly concerned with actual computation. You aren't identifying a distinction here.

Both Software Engineering and Computer Engineering exist, as sub-disciplines, but it doesn't make sense to argue that somehow studying Graphene (a chemical which exists) is Chemistry while studying non-blocking algorithms is only Applied Computer Science somehow just because such algorithms could be used on an actual computer.