You're either very young or naïve or both. Almost everything we do in this world has good/evil direct/indirect consequences. For example, should I blame you for polluting the planet because you are using an electronic device to post naïve comments on the internet that likely gets its energy by producing some sort of pollution? What about the vehicle you drive? What about the slaughters that take place because of your meat consumption? What about the carbon dioxide you breathe out that's toxic in high quantities? How dare you add to our carbon footprint!

In the end good/evil are myths. They are human constructs and they can change depending on time and place. Ethics is not a hard science and your belief that something is good does not make it a fact.

The military can cause a lot of destruction and grief around the world, no doubt, but it can also cause a lot of good and stability. In the real world there will always be "winners" and "losers" An action that benefits you may directly or indirectly hinder someone else.

Our military's mission is to defend our country and that means that sometimes other countries will lose if they decide to engage. Inevitably there will be innocent casualties. This will never ever change. It is an honorable thing to do what we can to minimize it but unrealistic to expect it to ever go away.

You will likely see the world in a different light the older and more experienced you get. You're not a good person. You're not a bad person.

You're just a person.