Hardly anyone voluntarily pays taxes for countries where they don’t live (or work). Most people wouldn’t pay any more taxes than they owe. Paying tax is not evidence that people value outsiders less than their fellow citizens.
I pay every cent of tax I owe, and not a cent more. And I am strongly against killing even one foreign citizen in the name of maintaining the perception or reality that America is strong. Killing hundreds of thousands of citizens of other countries to avenge the 3000 Americans killed in 9/11 makes me sick. For me it really isn’t a grey area at all. In fact my morality demands that if someone has to be killed, it is more moral to kill one of our own than an outsider. I would much rather those hundreds of thousands we killed be Americans. Not only does it provide a check against devaluing life, but it is about taking responsibility and not externalizing human costs of our actions. If (and when) drone attacks on American soil start happening, we will wake up to the costs of our disregard for human life.