Something we've found is that when the news about Israel is small, only the most dedicated people show up to talk about it. When the news about Israel is large, there are more people and they bring the bias accordingly. We saw this yesterday when the Huffington Post "world" section was in a posting spree, most notably being that the peace talks are finally underway.
But in contrast, the readership's reaction to Israel's freeing of prisoners was quite the opposite. Maybe they just enjoy being negative, no matter the topic.