He was talking about doing it without bots
Even with 2 bots theres still a max of 12
1 bot would have 12 in one game, the other would have 12 in the other
All actions and chat would be relayed and synced between them using the bot to talk for people that arent playing on the same bot and computers to simulate the actions of the people that arent playing on the same bot
Giving the illusion that all 20-24 people are playing in the same game
Its 20-24 because depending on the game you will need more computers, if its something like a maze you could get 24 people in, since theres only 2 teams, but every team would require another computer, you can count creeps as 3 computers but i dont think you can change their alliances so depending on the teams you probably will only be able to use the aggressive creeps as a computer
So 2 enemy teams (with people on both sides) would need 1 computer to take 1 slot in each game (making the max 11v11), 3 teams would need 2 computers (6v6v6 with 2 unused slots, or 7v7v6 if you dont care about them being even) and so on