There is a big difference between me being "Sir Markham of Viewhampton" online, and playing that role as a total dick, and me being me online and me being a total dick.
If I play Sir Markham as a dick who goes out, woes women, wines them and dines them then dumps them for the next bit of tail that comes along, that is clearly a part I am role playing because I am roleplaying him as that.
But if I come on here as me -- as Gabe and am rude, obnoxious, racist and a total twat then it is far more likely that is what I am like in real life.
If I roleplay a wizard in an online game do you think that means I can do magic in real life?