Someone shouldn't be able to have the @admin username
It's confusing for new users, and this instance in particular has 7k users but no interactions. It's a bot army, with the top user being called @admin.
For those of us who understand how the platform works, it wouldn't be an issue. However, if we want mass adoption of the platform, we need to take into consideration those who don't fully understand the technology and avoid situations that will lead to scams where feasible. Names of authority, like admin, root, super, etc., make a user appear to have authority they don't, which can mislead new users. ("Support our server by sending bitcoin to this address that is really my personal wallet" type scams comes to mind.) You could say that it's the person's fault for falling for it, but it's something that would drive people away from the platform which can be easily avoided in the first place.