Unlike the site you're reading, Fangraphs does not have an inherently negative view of the world. It's just that when your favorite team loses (and loses and loses), it offers an especially graphic view of the carnage.
This article in the Kansas City Star explains the Fangraphs methodology, based on WE (Win Expectancy) and WPA (Win Probability Added):
An average team enters each game with a WE of 50 percent. As the game progresses, this figure moves up and down, depending on inning, score, outs and men on base.
Let’s use the April 8 game between the Royals and Tigers as an example. The Royals led 2-0 entering the ninth inning, which means, according to WE, that they had a 91.8 percent chance of winning the game.
By the time Detroit’s Ivan Rodriguez stepped to the plate against David Riske with two men on and nobody out, the Royals’ WE had dropped to 71.9 percent. After I-Rod’s bomb gave the Tigers a 3-2 lead, Kansas City’s WE was 17.4 percent.
WPA doles out credits and debits for every plate appearance in a game according to changes in WE. In our example, Rodriguez would get credit for .545 WPA, and Riske would get docked the same amount for the go-ahead home run.
So what you have in WPA is a statistic that comes as close to perfect contextualization as anything we’ve seen to date.
By Fangraph's WPA calculations, Tuesday night's dogs for the Cubs were, in order, Rich Hill, Jacque Jones, Cesar Izturis and Aramis Ramirez. By my calculations, which don't involve any actual calculating, it's hard to blame Hill for his work on the mound, though his bunting into a double play was nasty.
For the season, Derrek Lee, Ramirez, Mark DeRosa and Michael Barrett have made the most positive contributions at the plate. Ronny Cedeno, Cliff Floyd, Jones and Matt Murton have been the dregs.
You could tell much of this from watching. But Fangraphs does a remarkable job of charting the disaster.