I use DotNetPanel (WebsitePanel now, as it has been renamed and released as OpenSource) and I really like the control it gives me and my customers. DNP shows you the permissions you have the ability to modify, nothing more, nothing less. If it were to show you all the user accounts or groups on your hosting space directory, you would be contacting your hosting company with concern as to what the accounts were. For instance, your host may require the use a specific backup user to perform backups of your hosting space. That being said, your host has configured their server incorrectly and there is likely a group on the ACL for the root of all of the HostingSpaces with write permissions. I have seen with other DNP installations, the Users group is on the c:\HostingSpaces directory with permission to write.
It will not go over very well, but, you need to contact your host and explain that you are able to write to directories within your site that you haven't explicitly granted write permissions on.
If they don't listen to you, change hosts.