Q:

Difference between active and passive groups in Atlassian Crowd

While it is possible to make a group in Atlassian Crowd active or passive, they are still synchronized with the connected Confluence instance. In Confluence there is no option for a state like active or passive, so I assume it is active there anyway. 
So what is the point of setting the status in Crowd?

A:

It seems to have turned out that although it is possible to set permissions for groups within the Confluence application, the groups are only a summary for the users and the permissions are not set at group level but are forwarded to the user level. I think Atlassian has created a workaround for enabling and disabling groups by simply hiding the group name when setting permissions. In reality, the group still exists and forwards permissions to the group members. 

