Hi --- I took a look at the comment you're referring to and it took place 7 months ago. The only thing we can surmise is that your computer, or the computer that you were accessing SCG with was logged in as you and someone used the same computer to make the comment with. This might have happened at a library, internet cafe, or other place where people share computers.
That's our best guess, and fortunately this hasn't occured again.