There are many angles to this. The first one would of course be what you said, there would be no choice otherwise. I think in general a deterministic universe w

There are many angles to this. The first one would of course be what you said, there would be no choice otherwise. I think in general a deterministic universe would not be too different from one with true free will, at least from the perspective of our current knowledge and capabilities. People would still make decisions - do one thing and not another - have ideas, talk about them, be influenced by others, just the ultimate root why things go one way and not another would be different. Even in a deterministic universe you still have to deal with criminals in one way or another, and you have to make the rules and implement them, and for making the rules you have to think about the nature of the universe and what that means for morality. The real mystery for me would here be, why would a deterministic universe bring about a system of morality that takes the determinism of the universe into account? Or more generally, why can you do anything useful in a deterministic universe? Why are your perception, your thoughts, and your words connected in a meaningful way? Why is it not the case that the universe is in state A, you perceive B, think C, and say D? There is one apple, you see two, think of three oranges, and say half a fork. Back to the initial question, you could also consider that you are wrong, determinism might be false and you have free will after all. It would then be a bit of a waste to not use your capacity and instead throw your hands up because you - incorrectly - think that everything is set in stone anyway.