In earlier news articles the journalist did report Callocchia was a rival but later articles mention that he was in the Rizzuto camp and was also seen by his side. The above article mentions that.
I guess he just liked switching sides. Perhaps he was allowed back into the Rizzuto fold because he wasn't directly involved in the killings. It didn't serve any purpose for Rizzuto to kill anyone who was even remotely involved in the coup, just its leaders and some of the hitters. But at the end of the day business needed to continue and Callochia proved useful.
"It was between the brothers Kay -- I had nothing to do with it."