At least for a while, custom servers were allowed, and players exploited that option to set up servers where only a small number of armed human-controlled players could mow down unarmed bots for XP. But the servers were permitting players to keep joining even after the armed slots had been filled:
That puts most players on the big bot team: weaponless fodder for the XP farmers, who I'm sure are delighted to have human targets join the AI horde.
What's really funny is that not everyone leaves after discovering that only a handful of players in the server are XP farming and they aren't one of them. I've stuck around and watched players desperately run at their tormentors with knives over and over. Somewhere along the line, a rumor must've started that typing "/switch" or "/swapteam" into chat puts you on the other team, because there's a lot of that. It does not work. I've also seen strings of players type "/gun," apparently hoping that the command will give them a gun. It does not.