>You don't have to do something yourself to hold 
the opinion that it's all right if someone else 
does it.<

 By holding that opinion you condone the action 
whether you particapate or not. By condoning the 
action you give it YOUR moral authority to 
proceed. If others object to the action then they 
are considered 'intolerant' by your thinking, 
thus immoral. Society is BUILT on this foundation 
of collective moral ideas; its called 
Civilization. (read some history of the Roman 
Empire, you'll know what I'm talking about) If 
this thinking becomes the majority way of 
thinking we will no longer exist as a people. We 
will destroy ourselves. History has proven that 
time and time again.