I like to think the link is that if people truly think that their discussion and what they've presented than they have nothing to fear. Nor are they willing to sacrifice their integrity for it.
The best possible way of doing this would be if the person is basing this argument from the basis of good intention and good will and that they know the subject is of good. But if you can't do that perhaps deep down in side you know there is something wrong with your position. If you still believe in it you ought to have a solid argument.
Not this every people make mistakes as if all mistakes are the same argument. A distracted mother caused a car accident that kill someone. A drunken driver killed someone in a car accident. Both are mistakes but they're not equal, if they were then one of them wouldn't be likely to have a harsher punishment.
Having a real name forces at person to be honest, civil and actually put real effort into the discussion.
I like to think the people who hides behind these fake names are more like those Klanmen hiding behind those white hooded costumes. I'm not alluding to racism but it is either because deep down inside they know they're wrong or they're not brave enough to stand on their own feet or unwilling to put effort into making a solid argument.