FYI: This reply was made a while ago. The link I originally provided caused the post to be automatically moderated
Battlefield is a simulator, which is why destructible environments are more realistic. The reason why it's also allowed is because many of the buildings serve little purpose when it comes to the change in the game's flow.
Call of Duty is not a simulator--it's an arcade shooter. If players could destroy buildings freely, then the map would become a flat, un-interesting mess and upset the flow of the game.
Consider what was said about Ghosts during an interview with Ruben
"Everyone knows that can happen there, and someone's going to use it intelligently," Rubin told Eurogamer "Some maps have traps you can set, that you can then use as part of your play strategy. So it's not always about destruction. Destruction isn't what everything is, from a dynamic maps sense. It's changing things. It's moving things. In some maps we haven't talked about, it literally is moving objects out of the way, or moving them back into the way. It becomes more of a map strategy rather than just, oh it looks cool to blow up a building."
Rubin said that they didn't want to make everything destructible, because that runs the risk of players leveling everything to the ground and making the map "just flat and not very interesting."
~RUGGED SAVIOR