Think of it this way. If someone gets hired after cheating on an interview, they'll presumably not be as good as expected. They'll get fired, and the company will launch another round of interviews -- this time watching vigilantly for off-screen cheating.
Maybe I'm saying that I reject the assumption that off-screen cheating is as effective as people think it is. (I really don't have any statistics for this, though -- does anyone?
I'm just making my own assumption that it's not having a hugely noticeable impact on the overall pool of hired coders.)
Either way, I can totally see why you'd be mad cheating exists. But maybe take some heart from the fact that employers don't like it either, and will be on the look-out for it? I mean, if you preemptively remove yourself from interviewing because "What's the point if there's cheaters out there" - it becomes a self-fulfilling prophecy.