Oh yes, I can see that it would allocate all users that have global rights, because that’s what “global” means. Otherwise it would only be global rights for the database created prior to the user. Normally though, you would have users configured with global rights, other than perhaps on a development machine.
I’m going to stop commenting here, it’s such a long time since I did this that I don’t want to send you the wrong way, which it seems I’ve already done a little.