From that source:
If you love liberty, if you hate war, you should at once withdraw
your support from the government. Withdrawing your moral
support isn’t enough — it’s your practical support that the
government feeds on — it doesn’t give a damn what your opinions
are.
This is something you must do because you know the
difference between right and wrong and you know, when you look
the facts straight in the face, that when you willingly give practical
support to the government you participate in its wrongs. But this is
more than a matter of personal integrity.
This is an all-or-nothing fallacy
It's not like 100% of taxes go directly to the military. They also pay for things that people would be happy to have, and that it wouldn't trouble one's conscience to pay for, like roads. Should one not pay for a road just because there's a chance that a tank might drive on it while heading to war? That sort of thinking leads to viewing civilians as acceptable targets. In this day and age, it's not okay to kill a soldier's non-combatant wife, just because she "supports" her soldier husband. It's not okay to bomb a school because they teach their children the pledge of allegiance. Heck, it's not okay to kill a medic on the field, if he's unarmed.
If it's not okay to target non-combatants that support, directly or indirectly, the military, then it would also be wrong to say that one who indirectly supports the military by paying taxes is a hypocrite when it comes to their conscience.
It's irrelevant for Christians anyway, because Jesus settled the tax question long ago. Pay Caesar's things to Caesar, but God's things to God.
It's also noteworthy that the religious institutions, and members of their
religious orders, are also tax free, and do take this vow of poverty that this author suggests.