"Enjoy your ban"

What's the point of players saying this? I see the being thrown around so much in games and it does nothing to help the situation. All it does it make someone who's doing bad or trolling just increase in intensity. Honestly, there's no need to threaten someone because chances are, they won't get a ban, and it makes it harder for me to carry. Someone who's mildly trolling may not group or contest objectives, but they would still clear out minion waves and such to elevate lane pressure. If you don't like it that much, report them after the game like all of us, don't make a hard game unwinnable please.