I quite agree that if all you care about is x-risk then trying to address that by raising everyone's living standards is using a nuclear warhead to crack a nut. I was addressing the following thing you said:

it seems weird to think that bringing third-world living standards closer to our own will lead to more involvement in x-risk intervention without there being some sort of wider-spread availability of object-level x-risk intervention.

which I think is clearly wrong: bringing everyone's living standards up will increase the pool of people who have the motive and opportunity to work on x-risk, and since the number of people working on x-risk isn't zero that number will likely increase (say, by 2x) if the size of that pool increases (say, by 2x) as a result of making everyone better off.

I wasn't claiming (because it would be nuts) that the way to get the most x-risk bang per buck is to reduce poverty and disease in the poorest parts of the world. It surely isn't, by a large factor. But you seemed to be saying it would have zero x-risk impact (beyond effects like reducing pandemic risk by reducing overall disease levels). That's all I was disagreeing with.