Why is it so that while we are told in the Acts and epistles of many false-apostles and false brothers, there are no specific names mentioned? Has this matter ever been considered in Christianity?
I see several possibilities:
- One major characteristic of the Gnostic groups was the lack of defined leadership1, so one might imagine that the false brethren may simply have been without definite leader. Considering that the Gnostic movement would have started by the time that the Johanine literature was complete, I think this should hold particular prominence in this discussion.
- There was a desire to generalize those who are proclaiming false gospels. By giving examples, they automatically include and exclude certain groups. While there are many ways of falsehood, there is only one way of truth. This is what was meant when the Council of Constantinople said, "One, Holy, Catholic, and Apostolic Church". Had they said, "this community" or "that community" and a third community came along this generalization makes it so that they might be automatically excluded.
- It is not charitable to write that such-and-so is a heretic. While that person may be a heretic now, a week from now he could repent (such as was the case with James "the brother of our Lord," who was a Judiazer until the council described in Acts). If that happens, then you have this message sent out to all of the Churches condemning this person unjustly. Direct condemnation places a major stumbling block on the road to repentance.
- Perhaps they were not well known:
- The false brothers were less known — it is quite possible that, since there was no Apostolic (and, by proxy, divine) support for their position, they were not able to gain notoriety save as individuals in the congregations. Everyone knew Paul the Evangelist. Not quite so many knew Joe the third heretic.
- John speaks of a separation with these false brethren. It could be that they were no longer a part of the Church in the formal sense, and so similarly, they would not have been as well known.
1.Pagels, Elaine The Gnostic Gospels
Here are some suggestions, none of which I am claiming as necessarily the answer:
- Naming people draws attention to them. The writers probably didn't want their readers going to find out what these people were writing
- Naming people makes them exclusive. If the writer says "don't listen to Marcus and Suetonius" that leaves Octavius free to spread his teaching. This is especially true since the letters were circulated widely, and the authors may well have understood that they were also writing for a later generation.
Pauls did name and shame Phygelus and Hermogenes for leaving him, and latter in the same letter, he mentions Demas (maybe the same guy in Col 4:14) who had deserted him.
 You are aware that all who are in Asia turned away from me, among whom are Phygelus and Hermogenes. (2 Timothy 1:15 ESV)
 For Demas, in love with this present world, has deserted me and gone to Thessalonica. Crescens has gone to Galatia, Titus to Dalmatia. (2 Timothy 4:10 ESV)
In political debates, candidates who wish to take "the high ground" will often not refer to their opponents by name. Indeed in the US Republican Presidential primary contest, when Mitt Romney was trailing Newt Gingrich, he started calling his opponent out by name, leading the media to call him "desperate." Once he was comfortable in his lead, he ceased to call his own name.
This, coupled with the expense of ink and paper would probably have simply led to the "omission."