If violent dictators can't trust that you're making a deal for peaceful resolution in good faith, then a lot of people are going to die to achieve that transition. If the only way out is death, they're going to take as many people with them as possible. Is that worth it, just to kill one rich guy?
Peaceful transitions of power always involve compromises. Here, they agreed to spare his life in exchange for the future lives of countless citizens. If they didn't want to agree to those conditions, they shouldn't have made the deal. It just makes it harder for this situation to play out peacefully in the future.
Why doesn't it mean anything?
It literally means that if NY ends DST, we will follow suit to match them. It doesn't do anything until then, if that's what you mean, but it still has actual meaning beyond political posturing.
It's also not what you said. You said NY had already committed to doing it (which they haven't) if Ontario did it too. I can't find anything about Quebec passing a similar bill, so I may have been mistaken about that.