How is champion balance not considered part of gameplay?

How is a champions balance not considered part of game play?

"First off, this is NOT a warning or punishment to your Boards account. Your discussion has been removed due to being posted in the wrong sub-section. We know you're passionate and we want to make sure that you have these conversations in the correct avenues!

Here's the link to your deleted discussion:

http://boards.na.leagueoflegends.com/en/c/gameplay-balance/UIaL2QJ9

A good place to post this would be in:

Miscellaneous"- Riots message to me after deleting my vayne QQ thread.