That depends entirely on the tactical situation. For example: On Stalingrad Kessel, the warehouses have just fallen. The enemy can now capture the north rail yard or the assembly hall. Do you defend the two newly capturable objectives or attack the warehouse?
Personally, I defend the two objectives. The warehouse combat conditions favor the Russians with their PPShs and PPDs. The longer range engagements in the North Railyard and Assembly Hall are more suited to the Germans. Plus, the Russians have to cross open ground to get to both objectives, which can be covered by snipers and MG fire from the admin building. Counterattacking will simply bleed reinforcements. AND you're at a reinforcement disadvantage as the Germans, so wasting them trying to engage the enemy on ground that favors him is just goofy, despite the other tactical advantages it seems to offer. On balance, I find the warehouses to be better to put up a token defense, but not to become preoccupied with. You may hold them for a long while, but it'll cost you in manpower and you'll eventually be overwhelmed.
The same is true on a map like Berezina where most of the recapturable objectives are ones that are difficult to recapture in the first place, and you're already at a reinforcement disadvantage. By contrast, the static defenses are more easily held and force the enemy to cross wide open spaces under your guns.
On the other hand, a map like Kaukasus practically demands counterattack, if only to help run out the clock and slow the enemy. Reinforcements on that map are relatively close, but time and positioning start in the Russians' favor. Maintaining that position is key to winning the map.
Even on maps like Berezina and Gorlitz, there are instances where "counter-attacking" can be useful. Not with the intent to capture a position (since many times the positions can't be recaptured), but simply to delay the enemy and buy time for the main force to dig in. That's not a counter attack, though, it's a delaying action.
Regardless, most players make no such distinctions and are uninterested in the tactical differences. The ones who are the subject matter of this thread are those who think "defense" means "attacking when your side starts with all the objectives." That's not defense, and often it's suicidal and a great way to lose the map. Intelligent counterattack or delaying actions are valuable when done at the right time. The rest of the time they just waste reinforcements.
But, even so, monster, don't think I'm lumping you in with the crowd that I think simply doesn't GET defense. You clearly do, you just have a different tactical opinion of the situation at times. That's fine by me. Reasonable people can agree to disagree, and at least you're actually thinking about the tactics, instead of simply saying "Man...I'm bored. I'm gonna go shoot something".
