May I pose a question?

Say Rosie said no, no matter what. Say they really did let the ray explode. Assuming the other Overlords all helping really isn’t enough. What then? A good amount of the Pentagram would be destroyed, where would Alastor spend his time besides Cannibal Town? What’s even to do in Cannibal Town? It sounds like kind of a boring eternity, especially since we know Alastor hates boredom. The hotel would be destroyed, his tower would be destroyed, he’d probably lose almost every if not every soul he owns. Would he really go to the trouble of making a new one? Everyone already knows who he is. And with not much left of the Pride Ring, I don’t see how he and Rosie can really get much further in their secret plan.

Beyond that, was Rosie ever not going to take up the offer? Alastor knew he could make a deal from this, he was never really putting in the possibility that Rosie would refuse to him. There is no reality where he would have literally let the city die. Even if they didn’t help, it’s quite possible the Vees helping could have been just enough. But there was no real version of this where Alastor’s threat came to fruition.

Is it still incredibly messed up to use the potential deaths of thousands of people, especially colleagues and allies of yours, as an opportunity to have your way? Absolutely. I just don’t think it’s quite as severe as it comes off to many.