"Let people play Disco Nunu if they want."
Let people run down mid if they want. Let people build Azir AD if they want. Let people build Riven AP if they want. Let people pick Teemo and play the role of Ward if they want.
Let people play how they want, even if what they want is to be the absentee in a 4v5. That's what that sentiment gets you. As an individual, it may sound nice that you have the power over 4 other players to ruin their fun with your own intentional poor decisions. But the majority, who don't take to the boards, don't tend to let that slide.
Saying, "let people play what they want," is not an excuse for people to intentionally feed and/or troll. Stop acting like it is.
You can play what you want against beginner bots, if you aren't ready for the responsibility of playing with and against real people.
For those of you commenting who are saying that "off-meta" isn't inting, first of all you have a misconception of the difference. An off-meta champion is a champion who is not doing well even with their intended role and build. Ryze has been off-meta for a while now, since he got nerfed from abuse in pro play. However, AD Ryze is simply trolling, since he does not have anything in his kit that coincides with AD items.
Note, though, that if the person does well and leads the team to victory, then they had the confidence beforehand to say they knew it would work. If they fail, and the team can't win because their jungler was executed 3 times by raptors, they did not go into the game with the intent to win.
And as for proof against your claim that playing off-meta isn't bannable, here are two Diamond level examples, one being the player who at the time was the number one Nunu player on NA. These players did not get to do what they wanted even when it succeeded, because going a troll build/role forces your entire team to play and pick around you instead of what they want. You say, "let people play what they want," but for 4 players forced to play something besides what they want in order to have a chance at winning goes against that sentiment.
