I keep them just fine. I have a theory. Most people get goniopora when they are new to the hobby, don't have enough experience with their care, and a tank that is not yet suitable{it needs to mature~ alot} Then everyone freaks out.."oh no..it's going to die!" It does die, but not because it is impossible to keep, but because of the aforementioned circumstances. Then that same hobbiest never tries them again, and warns others not to. So everyone thinks they are impossible, when in fact given the right conditions...they are awesome. The green ~ Stokesi are the most available, and consequently the hardest to keep. I have two different color alveoporas, a purple and a red goniopora, all are thriving. Check out goniopora dot org for more info.
Another thing that will cause them to die is improper handling & a damaged specimen to begin with. Care must be taken not to touch the flesh,hold by the base. They should be placed on a flat rock or similar, so the substrate doesn't touch them. They need meaty food such as DT's oyster eggs, frozen cyclop-eeze, mysis, lobster roe, golden pearls, etc. Rod's food is great, it has lots of good ingredients and breaks up small.