They're all rats. It just depends on who they ratted to. Some gave info to law enforcement, others gave info to their bosses and capos on fellow soldiers and underlings. A strong boss reigns not only through fear and respect, but also good informants, aka "rats".
And TommyGambino, Lucchese was the biggest informant of them all. He just ratted on mafia to the mafia. The people he ratted on didn't go to jail. They got whacked. So which is worse?
"For us, rubbin'out a Mustache was just like makin' way for a new building, like we was in the construction business."
