How to view calendar availability within organization

You can update the permission on the Default security principal, which includes every other user within the organization (so you don't have to add them one by one):

$calendars = Get-Mailbox -RecipientTypeDetails UserMailbox | Get-MailboxFolderStatistics | ? {$_.FolderType -eq "Calendar"} | select @{n="Identity"; e={$_.Identity.Replace("\",":\")}}

$calendars | % {Set-MailboxFolderPermission -Identity $_.Identity -User Default -AccessRights AvailabilityOnly}

Replace with "LimitedDetails" for the AccessRights parameter value if you want to display all the metadata.