And again - I make no distinction; car or bike. Also, you are only thinking in terms of filtering, and forgetting passing on the shoulder part.
If few bikes do it, why shouldn't some cars do it too... If I rip my car's a/c out and disconnect radiator fan, does that give me the right to pass all the dumb folks stuck in traffic, and cruise down emergency lane, all the way home?
If you're in your car, and there's an accident up ahead, just happened... You're stuck in center lane. Meanwhile, there's a steady stream of cars slowly driving down the emergency lane... do you not see how they are making it worse for everyone? And for no other reason but because they feel they are more important/smart/tough (whatever) than everyone else, including you. How can you not see anti-social aspect of this behaviour?.