Yeah, that’s annoying, but I’m often annoyed that the tag requirements that I want enforced are not enforced for admins, so it could be just as annoying to change it to give admins license to break the rules that they have tried to impose on themselves. 
And from the Jay-always-treats-feature-as-support department, you can also use Automatically add group flair to members’ avatars which is much less subtle, so another way to solve your actual problem is to let the flair do the job of making it clear who is staff.