Really? You think products to help people lose weight or stop smoking are even remotely in the same league as a "gay cure?"
How about a "cure" for being black? Or a "cure" for being a Christian?
Being overweight is the result of poor choices. Yeah, it sucks when people get picked on for it, but it is an unhealthy condition that can be changed. Offering people help with that process is not hate. Being gay is not a disease and it has no cure. Telling people that a basic part of who they are is a disease is hate.
Maybe Apple shouldn't ban apps at all, I'd prefer that myself. They've already started down that road, however, and hate speech isn't exactly an unreasonable thing to ban, if you are going to ban anything.