That uses the exact same synchronisation model? Only difference with peer hosting is that the “host” runs both the coordination server and their own local copy of a client that is connected to the coordination server. In old versions of Warcraft III you could be kicked by your own coordination server as host lol.
They are not RTS games. The engine they use is optimised for FPS/third person games. As such it works similar to how Diablo II/Diablo III/World of Warcraft/Overwatch works as opposed to Age of Empires, Empire Earth, StarCraft, WarCraft, e.t.c. These use a heavy server to run all game calculations and all the clients do is receive a stream of the current game state. This works for games with not very complicated game state, but struggles to scale very well which is why RTS games avoid it. For example it will not do very well with sending 1,200 Zergling around at the same time.
Yet hosts used tools to kick whoever they wanted from their games… They could also run all the maphacks they wanted without repercussions.
And this was with just childish people abusing the system. A malicious hacker could probably find some sort of exploit to potentially do malicious things to your computer or at least Warcraft III install, similar to what happened with the Dark Souls/Eldin Ring series recently.