There's a blunt reason for this, first and foremost: armies exist to kill people and to do so very, very well. The whole purpose of everything to do with an army is to ensure that when it kills people it does so with a degree of skill and efficiency that ensures that it does so for hopefully a short time that doesn't cost much. Whenever people speak of being on-target that means technology that ensures a human being is directly in position to be killed horribly by an expensive piece of machinery.
When people speak of tactics, that's how a small group of people go about killing another small group of people very efficiently, hopefully without many of their own people dying horribly. Strategy is how all that tactics and the intermediary operational level fit together. The thing is that the sole purpose of this is to ensure that soldiers kill other soldiers (and civilians, too) in the most ghastly efficient ways possible. Now, if people object to the term "killing" in regard to war, I repeat to you that in the words of Nathan Bedford Forrest war means fighting and fighting means killing. If the word bothers you, tough shit, that's what a war is.
The point of all this is that politics is supposed to be non-violent. It's the concept of people working together in civil institutions through legal means to achieve civil goals by virtue of institutions relying on non-violent institutions. So why the fuck does so much violent language creep in all over the place? Why should activities of peace have the vocabulary of war and bloodshed? IMHO at least in the USA this has to do with the juvenile, spoiled brat nature of the US political culture, one used to greed and all manner of indulgence but not used to the consequences of its actions.
I'm not sure of the extent to which this exists in other countries, but at least in this one it's because in my own opinion (and I say this regardless of who uses the rhetoric, it's weird coming from the mouths of both Dems and GOP people) the USA's political culture promotes adult children who don't have the intellectual ability or the courage to make a real decision, and they cloak this in harsh rhetoric to cover up a substantive emptiness. Your thoughts?