To answer the question in the title while ignoring the podcast, as others have here;
Leonard Nimoy was retired and only making occasional cameo appearances, and was older than the life expectancy of his demographic when he died. His death was certainly a tragedy for his family, and is disappointing news for anyone hoping to see him make another cameo appearance as "Old Spock" in the next Star Trek Reboot film, but feeling grief at the death of people you never even met is just one of the worse parts of the insanity that is celebrity culture, and we should actually be feeling about as we do for the average random stranger hundreds of miles away who dies at an age that, "until the blessed day when science can finally slay that dragon" [http://www.nickbostrom.com/fable/dragon.html], is normal or actually older than average.
Meanwhile the dress is actually some of the most interesting kind of news - "oh look, our human brains are weird in this way many of us weren't aware of before!" - and is the sort of thing that should take priority ahead of 90% of the sort of shit that ends up on headlines, because knowing your brain is fallible and learning one of the ways it tends to fail is extremely valuable.
Of course, that's more a response to the message of the rhetorical question (message being "hey, this useless thing was smaller news than this important thing, screw whoever was responsible"), a response more aligned with reality would be; The Dress was a flash-in-the-pan internet meme that exploded and disappeared in less than a day, as a thing that everybody mentioned but only reported on as far as an explanation of what's up with the picture and then forgot about, with slower-to-react media doing that days after it flashed through tumblr, and from certain perspectives that can look like a huge news craze. Meanwhile Nimoy's death acted as a typical news story would, with a slower but more evenly dispersed spread.
