DiamondFire

Psychology nerd here, I researched it a bit, you might find it interesting! https://www.verywellmind.com/the-color-psychology-of-red-2795821

Red is probably just associated with importance, with the admin team being an important focus in maintaining the server, so that's how it could be correlated haha. Basically passed down by people with time, almost becoming a tradition to use it for these things