Ethics/Logic Puzzle (Not Really Complicated)

Group A and Group B have been at war for decades. Group A uses weapons much more advanced than B and fires only at targets that present a threat to citizens of Group A, occasionally inflicting damage on civilians and civilian property. Group B, outmatched militarily, targets Group A civilians almost exclusively. Does Group B have any standing to object to Group A's causing unintentional civilian casualties?

The Israel-Palestinian issue is far more complex than this exercise, but I cannot understand how Israel can be blamed for firing on terrorists, even if the terrorists are launching rockets from crowded neighborhoods and public services buildings. Civilian deaths are a tragedy no matter whose civilians are dying.

For the record, Palestinians can stop this whole charade tomorrow: if they round up the terrorists in their midst and begin policing their own, Israel will immediately be forced to make huge concessions like opening checkpoints and removing security restrictions. The ball is in the Palestinian's court.

See here for a related read.