Funding someone does not make one responsile a single bit.

I am not responsible for an act you do with the knife I sold you last week, unless I did it in consent of you commiting the act. My parents aren't responsible for the acts I do.

Only when there's power, there's responsibility. Taxpayer does not have power over military, hence why taxpayer has no responsibility.

I see it differently. Without the tax money, the military could not operate. When I choose to pay our taxes, I am choosing to give money in support of the military's operations. I may disagree with the military's actions, but I choose supporting them (a little bit) over putting my life at risk by not paying. In that case it is a lose-lose situation.

So what do you propose as an alternative to this? Not paying isn't really an option. Move and renounce citizenship? (Remember, US has global taxation for citizen.) Not really a viable option to affect change, as you lose your right to vote, etc.

I do not think there is a nice alternative. I think we should accept that we share some responsibility for the actions of our home countries. If a political group could organize enough people to withhold their tax payments as part of a protest against a certain military action, that might cause enough of a disruption to stop it. Alternatively, it might just get everyone involved thrown in prison.