Good news don't have much of a positive impact on price. Not because there's no one buying the news, but because it's almost always offset by those selling the exact same news. And then bad news (or even no news) have a negative impact on price, as traders almost always seek to find another profit opportunity (a good pump), which very seldomly happens with Bitshares.
Ok, it's not a very scientific reasoning, but it's a layman theory lol