Yeah, it greatly depends on where and how the dead appear. Can they be reasoned with? Frankly, any pre-civilization cave-man would probably drop to their knees and worship us as gods. Especially the fat people, who to them would probably appear as the apex of all humanity could create.
First, where are they all appearing? I'm assuming it's not 100 meters above Point Nemo in the pacific ocean. Are they returning to the closest point where they died? If so, sucks to be in Africa and the Middle East, but what else is new? Are they spawning out of static locations at a set rate? Seems kind of easy to just send a guided missile every thirty seconds or so at that spot and wait for the survivors to drown in a crater filled with a slurry of human body parts.
Assuming they're brainwashed, then we're just talking about a zombie apocalypse style horde, but made of frail, living people? Tear gas the lot to take the fight out of 'em, then send in the machine guns. Unless they're waging guerrilla warfare, modern militaries care not one whit for the struggles of untrained masses of rabble armed with melee weapons. They'd run out of bodies long before we'd run out of bullets.
Honestly, the greatest damage would not be their ability to attack us, but their ability to disrupt the fragile network of supply chains that keeps modern society fed and warm. Adding 1,500% greater resource strain overnight on food, water and basic survival necessities would see towns stripped bare of all consumer goods within days. Then, those outside of the reach of government held stockpiles would simply starve to death in the coming weeks.
So yeah, probably we'd see a critical global resource collapse, but the strongholds of modern civilization would survive, and eventually reclaim their territories. Not because the masses of dead humans are dangerous, but simply because they could get hungry.