A game would keep people entertained or engaged in some way, some kind of focused shared activity. But to 4chan, coordinating with other anons about what YouTube comments to spam, what subreddit to brigade, that was the game. Organizing a personal army of trolls (yes that personal army) was the whole point of being there.

In your analogy, a game of LoL takes place where all 10 players don't play the game, they use global chat to decide on raiding Battlefield, DotA, or Overwatch. They then make a bunch of accounts, join some games, and rile people up with hate speech. Then they go back to LoL to share how angry they made other people.