Does it matter if no one knows his original name?
It's not as if he doesn't have a name, its just not his original one.
People change their names all the time if they don't like what they were given, maybe Satan did the same.
At the end of the day, Satan has a name - Satan.
If we're going to get picky we could also say that God has hidden his own name, since no one knows how to pronounce it. It doesn't matter though because He's been given a name.
What's the big deal?