Ive never heard anything like them ripping open corals for food. They will pinch the food from the mouths/tenticles of corals though.
There is really no need to call them "horrible" because alot of the time this is based on personal experience/opinion. It also depends on your taste, and if you want a passive cleaner.
Id say they are more suited to a FOWLR with no predators, or a reef when they are small in size.
I used to have a Coral Banded Shrimp, and I loved him. He never harmed a thing; except for me on occasion while rearranging the rock their huge arms aren't for just attracting mates.