As much as people hate it when the enemy faction has large numbers and uses those numbers to their advantage, it is a legitimate form of combat. Zergs are huge groups of average joes, skilled ambushers, newbies, and whatnot. In ESO PvP, they are often the other factions' most hated form of warfare. Zerging is actually called swarming in military terms, and is used in actual combat. Counter-zergs or swarms are just as real.
I am an Ebonheart warrior, and I always hear that AD and DC zerg their hearts out, and the same nonsense from the other factions. Truth is that all 3 factions zerg. There isn't that one faction full of angels who don't zerg at all. They all do it. I've seen DC and AD do it to EP, and EP do it back. It's large-scale PvP for ya.
For the love of Kyne, buff sorc. PC NACP 2100+Star-Sïnger - Khajiit Magicka Sorc - EP Grand Overlord - Flawless Conqueror vMA/vBRP/vDSA no death/vHel Ra HM/vAA HM/vSO HM/vMoL HM/vHoF HM/vAS +2/vCR+3/vSS HMs/vKA HMs/vVH/vRG Oax HM/vDSR