I'm a little bit on the fence on this one.
I don't think there's anything wrong with offending religions blatantly, as long as it fits with the story. Happens all the time, such as in Call of Juarez where you can walk around shooting people with your left hand and reading from the bible with your right hand about how God is cursing them.
On the other hand, there is a problem if you covertly & intentionally aim to offend people. For example, scribbling anti-semitic messages to fill space on a texture where the story does not call for such things.
And on the third hand, there are people that easily get offended and would require you to go very far out of you way not to offend them (such as people who absolutely hate sex and violence in video games).
However, Infinity Ward's case is very much in between these categories.
The game is based on reality, so obviously there is a place for religious symbols, figures, and wording to be used in the art design.
Even if Infinity Ward knew that Muslims would take offense if their religion is referenced in a room with a certain type of plumbing, the picture frame model could have still very easily found its way into the design of a bathroom later on, by accident.
The offending content being so obscure and "ticky-tack" in combination with the likelihood that the model made it into the bathroom simply to save on asset design leads me to believe that Infinity Ward had absolutely no intention of covertly offending Muslims.
With that being said, was Infinity Ward correct in pulling the offending content? Sure. I mean, at that point it is just a matter of keeping your customers happy. I don't think anybody who's not Muslim gives a crap if the religion is mentioned in the bathrooms of the game or not.
So if the business of the offended customers is worth more than the cost it takes to change an arbitrary part of the game that they find offensive, you should obviously appease them.
Taking the entire map down until you fixed the problem seems like the wrong way to go about it though. I would have left it alone until the "fix" was ready to go live. There's always the possibility that the offended group will be irrational in understanding why the content isn't immediately taken down, but you shouldn't sacrifice good business practices to accommodate irrational people.
On a side note, the guy who made the YouTube video seems rational enough, and even mentions that he didn't want the map removed completely. Not sure why he mentions terrorists in his caption, lol. But I assume it has something to do with the flame he must be catching on his YouTube video comments.
Kill Every All