only him. I am not sure if is a hack or if the map is some kind of modified for slot 4, since this map is not the regular redball but behaves like regular redball.
As we said in the past, this is a custom map, not an official one. As you can see at the top, there is no map image (only official maps are recognised by the Gamereplays system).
As others have said this is the modified redball, the host of the match gets 999999999 resources or whatever. You can simply not join him as others said.
https://steamcommunity.com/profiles/76561199221121746/
It's seems this guy have this map modified by some reason. It's just a joke playing like this.