It's a genetic defect. It doesn't have to intentionally be bred into something, it just pops up randomly in many species of cichlid and non-cichlid. IT HAPPENS. Not a big deal.
I picked up a SB texas from a batch at Petsmart once. Little guy didn't last long as it suffered some type of swim-bladder disorder. I've also come across short bodied firemouth, Xenotilapia sp., cobalt zebra, Geophagus sp., Gymnogeophagus sp., frontosa, brichardi, several species of catfish and even a pike. It's not very appealing, aesthetically - at least to most, but some people dig the novelty of a freak of nature.