^Of course they're unsatisfying. Nobody's claiming they're a complete solution; on the contrary, the researchers know there's still a vast amount we don't know, and that's why we're trying to find out. Science is about asking questions, not claiming to have the answers. "Dark energy" is just a placeholder for a principle we're still trying to identify. It's like "Here be dragons" on an antique map. It's not a claim of certainty, but an admission of ignorance.