About the potential ddossing. You dont have to explain to me how the internet works.
Its not about the host having access to your IP. Its about it being displayed on their screen when they are running the game. This could lead to someone screenshotting, recording or streaming (unintentionally) displaying others IP adresses. By merely displaying the IPs in an admin file the host will not be hindered when they do need IP adresses, yet potential ddos risk is lower.