When they started doing these tournaments over a decade ago, esports LAN tournaments was barely an industry, and crowds were small. Also, MOBAs are unlike many other esport genres [1], in that the two teams have partial information about the state of the game, and illegally getting information a few seconds early can change the entire outcome of the game [2].

Meaning there was no one in the world who really knew how to build such booths. Moreover, they discovered required features of the booths over the years. In such a scenario, the early mistakes are very understandable.

[1] Think Street Fighter, or FIFA

[2] I don't think games like Starcraft has such low time tolerances on information flow. Even cheers in Dota can be enough of a clue.