Of course those shows are stupid. However, when taken as a whole, many situations are laughable. Besides, I bet that most of the recorded events end up in a good way, so, if you find Alterego's story laughable, you should be amused by those stupid shows as well.
As for laughing out of helplessness, I think that there's a difference between nervously laughing while being pale and unable to move and laughing out of amusement (not nesecerally loudly) while approaching to help or just causally walking by.
I'm rather indifferent to anyone's pain, including mine. When I broke my arm by falling from a skateboard, I haven't cried like that overweight boy from one of the links I posted. I was angry that it ended that way but besides that I was calm. And I stayed that way until my concerned parents took me to a hospital where I received my first plaster cast. And boy was I all over the place there. Everything was new and interesting for me. I was fascinated with my arm scan and enjoyed the warm setting plaster too. Actually, when I think about it, others were always more concerened about my health than I was.
As for my reaction to the pain of others, I can either laugh if the event was funny (to me), try to hold my laugh when people complain and tell me what had happened to them, or approach the scene driven by curiosity and urge to see what had happened. I'm weirdly attracted to observing various injuries. I don't want to attatch any labels, but it might be an indicator that I'm rather sadistic. But don't get me wrong, I can help people in need with ease and it's not like I always scan my surroundings for injured people nor I always want so see some injuries or laugh when seeing an accident happen. I might as well ignore it completely and continue doing what I did before.