But when "collaterals" happens, my problem is not "that will not convince people", my problem is "collaterals happened".
Ah, I see, you were talking about the morality. I have no problem with saying "accidentally harming people who don't deserve it, is morally wrong". But that doesn't really get us anywhere, because we're then confronted with the horror of collateral damage being necessary.
Once something is necessary, it's a question of realism (in the political sense) and then we discuss it using realism. We would refrain from causing collateral damage for morality's sake, except that we cannot. So, why? Because there's a larger fight that needs to be won. Then we're entering realism, where "what's the value of limiting collateral damage"? Well, the value is that limiting collateral damage gives you tools with which to win the larger battle, which spill into actually causing less collateral damage.
Preventing collateral damage out of morality will have the same effect as doing so out of realism, but trying to convince people to behave morally rather than realistically is only useful if one wants to create window-dressing for the realistic behavior.
In my experience, people don't care about moral arguments or hypocrisy, not really. It's consequences they care about. We like pointing out other people's hypocrisy, but our own hypocrisy rarely motivates changes. Selfishness is too powerful.(you can call it more commonly "hypocrisy").
It's why the world is so crappy. Moral arguments are insufficiently persuasive, even within political circle - nevermind across them.