I'd have to agree with this. Player vs. Player is really irritating, especially because I've had a few people randomly kill me when I'm trying to build something! It's even more annoying when they're "invisible" (still loading I guess) and you can't see them. Plus, it seems really buggy; for example: Yama was way out of arms reach, facing AWAY from me and building and it was still saying he was hitting me!
It would be fun to be able to kill animals & monsters, but I agree that players should be invincible and that pvp should be removed. People are abusing it, imo.
Got killed from 'friendly fire', then some noob killed me at the spawn within two seconds, and the game crashed.
Also, things are too hard to kill, imo. 9 hits to kill a sheep(chicken)? blah I say.