Concerning the comments about Left 4 Dead 2, the blogger does not actually state what part of the game is racist. In fact he only successfully manages to register his displeasure with the game being set in New Orleans such a sort time after a natural disaster and tragedy.
However, the blogger does imply that the game may be racist when he states::
"Set in New Orleans, players will have to fight their way through hordes of zombies - with several of them who appear to be African-Americans."
Here we can determine that he finds it jarring that several of the zombie character models appear to be African Americans. The consequence of this ironically shows that in fact the blogger, and not the game, is thinking in a racist manner.
The blogger is suggesting that if one race of people were not depicted then it would be okay, hence the blogger is determining who should and should not be depicted based on their race; this is racist.
Consider the 2007 drama K-Ville, which is set in New Orleans. This has not been decried as being racist, why? It depicts African-Americans as criminals and makes very specific references to the significance of Hurricane Katrina. Not to mention the fact that it was made 2 years ago, a much shorter time after the tragedy.
If Valve were to depict New Orleans without any African Americans would surely be racist and ignore the history and cultural heritage of the area.
Basically the argument of a racist undertone in Left 4 Dead 2 is completely unfounded and not even well argued.
As for Call of Juarez, it is set in the time and period of the Civil War and telling the story of two brothers who were in the Confederate army. The racism is merely a portrayal the situation and attitudes of that period, nothing in that is the game being racist; the game is not in any way condoning the actions of the Confederate, nor they are not suggesting that we sympathize with their actions.