I don't see how it could be perspective. The Slovenian's ski and glove are both clearly ahead of the Korean's. From what I heard on the broadcast, any part of the equipment or rider counts. The only thing that I can think of is, maybe, the red line isn't precisely where the finish line is--maybe it was painted imprecisely, like lines on a football field, or it warps as the snow shifts--but, even then, it's hard to imagine, from that image, that the Korean beat him to wherever the invisible line was.
I wonder if the IOC will do something. The Slovenian should get at least a silver, since he would've been assured of at least that if he'd won that semifinal. I'm not sure if they'd strip it from the Korean, though, since he did nothing wrong. Letting him keep it and giving a second silver to the Slovenian might be best thing all around, IMO.