I interpret it more like "If you wouldn't want your mother to see you do it, then you probably shouldn't."
For what it's worth, while I absolutely love my civil liberties and freedoms, I do believe in accountability for one's actions. If I say something indefensible against a minority group, I believe that I should be ready to bear the consequences of my racism. I can either defend my actions with an intelligent argument or I can't. I shouldn't be able to just say "Oh. That was somebody else."
On the flip side, if I'm arguing for a controversial idea, then I will expect people to take the argument as insincere if I'm not willing to attach my name to it.
Anybody can say something anonymously, in the same way that anybody can pirate music. The people who are purposefully exercising civil disobedience are the ones I respect, whether or not I agree with their cause. That said, very few people actually practice civil disobedience. They download music and say 'Damn the man' wherever they can, but what actual GOOD does that do?
And just before anybody attacks me for trying to take away their right to privacy, I fully understand and support that it is our right, generally, and would never knowingly support/elect/fund or petition anyone trying to take that right away. But for me, personally, I think the bigger statement is always going to come from someone who is willing to risk their reputation to make a statement that's unpopular.