Mobs don't instantly depop if you wipe, they walk back to their spawn point, and then stand there for a bit. And I guess you are on the side of people who spend 2 hours fighting something with an alliance I could solo in 10 minutes, so I guess you wouldn't understand what I mean. But the basic idea is that it's ignorant and rude to zombie hold stuff when people are waiting for you to be done, that's why they will steal it from you and kill it, not because they are bad selfish people, but because you are. (most of the time this is true anyway, there are some real jerks around)