Well if the only reason you PVP is to cause your opponents to lose XP then you're missing out. I PVP so I have the feeling of pride at triumphing over my enemy. I PVP for my ego and the experience of besting my opponents. I PVP for the challenge of overcoming the scenario. So XP loss is a de-motivator to PVP because why bother when I'm probably going to lose an hour of work. Might as well ignore that person flagging on me because it's just a trap anyway.
When the event ends people can go back to complaining on this forum and in game about how no one wants to PVPs their swarm...