This is the core of the misunderstanding. The legitimate "Nexus Admin" system doesn't need an executor at all because it's designed to be embedded directly into the game's code. Developers add it using Roblox's built-in require function to load modules they trust, without needing to bypass any security.
However, as with any large-scale project, managing and administering such a vast and diverse environment was a monumental task. The developers needed a robust system to ensure that their creation remained secure, efficient, and, most importantly, fun for all users. This is where the concept of a script executor came into play.