Extremely sorry about that, but maybe you don't like users sharing their entire computer; after all, when they do that everyone in the meeting sees everything
that happens on the shared computer, including such things as a Microsoft Outlook "toast" popping up to announce a newly-received email. Because of that, you might prefer to limit users to sharing just a single application; that way, people in the meeting
only see the activities that take place within that application. In that case, just set EnableAppDesktopSharing to SingleApplication:
Set-CsConferencingPolicy Identity global EnableAppDesktopSharing SingleApplication
When you do that, the Desktop option will no longer be available under the Share menu: