I think this Free look button (*) is disabled in MP on purpose,its not a bug...
If u play PvP U dont want this free look,because it is possible to look behind objects.
(same reason why we disable 3th vieuw as well in matches)
Also notice the difference between DisableAI and DisabledAI.
DisabledAI = 1 means only HI (Human Intelligence),written in description.ext
Unit DisableAI section is a command,can not be used in description.ext (but in scripts-triggers...)