There's an important thing to understand about this topic. The tendency is for the individual to look at this subjectively and in temporal isolation. This is especially true if he is the recent victim of a horde bang. But, step back and look at the bigger tactical picture. Gang hording a single con is bad tactics. The more enemy that engage a single bandit the more vulnerable they become to any other enemy bandit that approaches and the less likely they are individually to score a victory.
For example, say I am wandering into an area, there's 1 friendly at 12k, 5 enemy at 15k and me at 10k. Well, the 5 enemy at 15k don't notice me as I am far away, but they all pile on my friendly who has no choice but to spiral dive defensively in my general direction. I come in and kill two or three of the enemy that blew all of their E chasing my friend as they are now below me, and my friend is able to escape with me as cover. By all attacking my single friend they unecessarily put themselves in a position to be attacked at a disadvantage. The enemy bandits only had a 20% chance each to score a victory, all factors being equal.
Now say instead, the 5 enemy do not all engage my friend, only 2 do. Now my friend is engaged and as I approach I am confronted by 3 enemy higher than me and either forced to engage or egress. Either way my friend and I are in no position to mutually assist one another. We'd both be doing well to just survive an encounter with multiple higher enemy. Both groups of enemy were able to attack with the advantage.The enemy bandits on my friend had a 50% chance of scoring a victory and the ones on me had a 33% chance.
The second scenario is actually how it happened in real life. Only the force necessary was applied, the remaining elements stayed as top cover to confont other, hitherto unknown, bogeys. So, in the game, anytime you see gang banging you can take comfort in the fact that they are relatively ineffective because they are resigning themselves to a much smaller fraction of kills and making themselves much more vulnerable to being killed. In essence they are making things a lot easier for you and your team than it would be if they didn't gang-bang.