it's kind of a miracle that it doesn't get traced to the other two as well.
There really should have been a scene added of one of the two of them pulling Tommy aside and saying "Listen, you can't kill this guy. He's made. Or, if you are gonna do something, at least leave us out of it.
In reality, Jimmy had taken over Batts' rackets while he was inside, and Jimmy being the greedy, vicious thug that he was, didn't want to give them up to Billy upon his return. He planned to eventually whack him out, and the insults toward Tommy just escalated the situation.
According to Henry Hill, Tommy was an extremely short fuse, and he would snap at a moment's notice. People were usually nervous around him, and even light hearted jokes would set him off. Once Tommy started in on Batts, Jimmy just backed him up.