If you are seeing these users in the admin console it is expected. the ‘undelete’ button would then be active for these deleted users so there is a function to ‘restore’ in case they were deleted inadvertently.
You should not be seeing these deleted users in the main application USERS list. if you are, how did you try to ‘delete’ them ? perhaps the user you were logged in as didn’t have the appropriate ‘rights’ to do this ?