RE: How did this passive display adapter do the job that should have needed an active adapter?
DisplayPort interface typically display the "DP" logo next to the port itself on the outer casing. A "DP++" logo indicates that your computer supports multi-mode DisplayPort for use with different data types.
DP++" logo also means that Display port to HDMI has the optional audio channel. Since I do not see that logo I would say NO.