I think you, being a person who wants to see the US not kill people but help people, should be behind this program 100%. The missile defense program isn’t an offensive weapon; it is a defensive weapon that will save lives if and when a missile is launched at the US or one of its allies. You are an American right? You do want to protect the American people right?
The likelihood of a world ending salvo of nuclear strikes is pretty remote now days. Russia isn’t interested in playing the MAD game anymore than China would/will be if/when it builds up a sizable arsenal. Russia and/or China might be willing to help other nations “covertly” acquire the ability to launch a missile at the US, as evidenced by the growing threat from North Korea and Iran.
We can ill afford to wait until such irrational nations or possibly terrorists groups are capable of launching a nuke at the US. We need to do the research today and further develop the defensive capabilities today that will be required to protect the US in the future.