In this day and age the remaining US Mafia families don't even kill rats living out in the open. So you can understand their priorities in killing someone who's bumped off an associate.
Times have changed. Different priorities for a different time.
What I mean is like if a rival gang member murders one of your close associates, you might have to murder him just to show that your family will not put up with such acts. It's not out of revenge, but out of necessity to keep your business going.
"I die outside; I die in jail. It don't matter to me," -John Franzese
