Zoom wants the Flash dead. We don't know exactly why yet, but clearly he or she has a beef with people who run fast. Instead of doing Flash in themselves, Zoom has been sending people from his world through tears in reality into the Flash's world to try to snuff him out. The question is, why? In the second episode when Zoom sends Sand Demon through the portal, Zoom comes along with him to Earth-1 to tell him to kill the Flash if he wants to go home. Zoom is literally there, why can't he do it himself? It certainly can't be out of fear of losing his powers. Jay lost his the moment he came through the tear, but Zoom seemed completely unaffected by it. If Zoom is full power and capable of running faster than Jay's approximation of just under the speed of light, there is quite simply nothing stopping them from bringing the fight to the Flash. Zoom even has a portal in Star Labs that he could step through at any time.
Any time I'm not writing, I'm likely arguing about children's cartoons with strangers on the internet or staring at my ceiling and wondering where it all went wrong.
