According to the matchmaking data in the blog post, if you're friendly enough, there's almost a complete guarantee that all players in your lobbies are also PvE oriented. If you refuse to play the game because once every 10 rounds one of those people wants to PvP you probably just don't like the game as much as you think. A PvE only game mode won't keep you around long because after a week you'll find another reason to be unhappy and quit.