No, it's not really that type of issue at all. If you're close enough to attack the ships you're close enough for them to aggro you. Picking off and isolating individual ships is just not efficient, especially if you're trying to complete 100+ kills for a massacre mission. You might not get aggro that way but you will be taking dramatically longer to kill ships and that's not a solution.
You also don't seem to properly understand the situation I'm describing. It's not that I'm choosing a side in the middle of the CZ and suddenly getting aggro because I'm the closest ship for them to target, it's not that I'm having only one side spawn in and causing aggro because I'm the only enemy ship within range, I'm just killing ships in a CZ and after a few kills I happen to be doing enough damage to become a priority target. I don't know if your setup just doesn't cause enough damage or if you only fight at the edge of the CZ but regular CZ combat very much can draw the type of agro I'm describing if you're using a fully Engineered ship.
Under normal circumstance that aggro wouldn't normally be isn't an issue but the aimbot NPC Eagles with railguns are really annoying and there's just no legitimate excuse for it other than bad game design. I can deal with it by using a shield cell and trying to finish them off quickly so it's not like they're causing me any serious trouble unless there's more than 6 of them but the NPCs quite simply shouldn't have that level of accuracy and that is what needs to be fixed.
I generally fly CZ's with a fully engineered Corvette or my engineered Gunship. Either way, I do a lot more DPS than your multicannon Vulture. (Not boasting here, you're the one who tried to make it an issue) I also fully understand the situation you're describing, but you don't seem to.
They're not all swarming you just because you're so awesome and do such amazing damage. They're swarming you because you're not paying attention, and you're letting yourself get swarmed.
If you're the highest threat nearby when an NPC finishes their fight, yes, you will get swarmed. It has far more to do with range than your leet dps though. Solution: manage your positioning better. Fighting is far more about positioning than it is pulling triggers.
Also, you can't argue that your method is both faster and superior yet also makes you die all the time. Those two are mutually exclusive. Either you're wildly overstating the railgun problem, or you're wildly overestimating your own combat effectiveness. I'd guess a little of both.