Anna Nicole:
stripper bimbo of no discernable talent, "famous for being famous", lived a sad, pathetic life. Was a punchline long before she came to a sad end.
Barbaro:
Champion, might have been historically great, suffered hideous accident yet gallantly held on until medical science could do no more.
Aside from the fact that one is a horse and one is a human, I'd say the reactions are fairly normal.
Gallantly held on? What, is there a high rate of injured race horse suicide? Every day the horse woke up and said, "Dammit, I've got to FIGHT this thing, man!!! I can't give up now!" A little bit of extreme anthropomorphism there, don't you think? Seems to me the owners kept the horse alive until they exhausted all options. I don't think the horse chose one way or the other.
Smith might've been "famous for being famous" but she was a human being who leaves behind an infant daughter. That sucks.