I don't understand the objections.
Individuals don't have much say over what happens in govt. Theoretically we can express our wishes but in practice we get one lot or the other lot and then they get on with doing whatever they fancy doing.
An awful lot of people didn't support the war in Iraq - there were protest marches at the time - and a lot of them were labour voters and turned away from the party because of it. Meanwhile we know that a conservative government would have done the same ie gone to war so it's the same result whatever colour you are.
That's all that.
What we do have power to do as individuals is vote with our feet when it comes to the products and services we buy. Irrespective of the fact that our government went to war, a war which would have happened whoever was in power, there is a possibility as an individual to say "I won't buy / use a product which supports practices that I disagree with. If you don't support the use of cluster bombs then withdrawing support from institutions involved with manufacturers is a fairly simple thing to do (well assuming there are any!). I don't understand why people wouldn't do that on the basis of what the previous government did. Two wrongs don't make a right and all that.