Erm, you do know that Anglicans and Roman Catholics have fought, just not in the US, right?
Oh wow I never knew that until you informed me about it, perhaps in your mighty wisdom you could point out which times that was purely because of Religion, and which ones were because of political motivation?
I'd also note that while the poster I was responding to stated Theocracies since they for all practically don't exist, it's a bit like trying to determine if green unicorns are violent. However his post made it appear that theists are so terrible they are just itching for an excuse to attack each other over the littlest differences in doctrine. This clearly is not true, or instead of having to hunt for these fabled wars (I'd note that even asking for a list of pure religion based wars no one has yet come up with one) we'd be able to point out countries currently at war over religion.
Even if we look at countries that are close to theocracies around the world, both past and present, they don't have a history of attacking other countries because of religious reasons. Who has the Vatican City declared war on? Which Islamic "Theocracies" are warring with others? Again they don't really have them, but if we look at the closest, such as Yemen, Saudi Arabia, Mauritania, or Oman, the only one that has been involved in a major war recently is Iran, and in that case the most secular government in the region at the time, Iraq, attacked them.
We see similar trends throughout history, very few of those groups that have come closest to theocracy have been expansive, and in general when they have become involved in wars, it is wars of defence against the larger territorial powers around them who decide to destroy them for political purposes. One of the few examples that oppose that was the Taiping Rebellion a short lived Theocracy/Communist rebellion based in China. But then others here have already noted that rebellions don't count right?
And that the only reason the JW's and various other fringe Christian sects are in the US is because other Christians were persecuting them in countries like Holland and Britain?
Ummm, you do realise that the JW sect was created in 1870 in Pittsburgh, Pennsylvania, right? In fact they have never been persecuted in Holland or Britain. What persecution they did suffer was in countries such as communist states, Nazi Germany, and interestingly Canada where they were interred during WW2 due to their objections to being conscripted to fight. Similarly Mormonism was developed in the US.
I would further note that even if you consider all the sectarian violence during the Middles Ages, which was really political in nature as groups broke away from the control of the main central European power of the time, the Catholic Papacy, WWI and WWII, both secular wars, still killed more people, in fact as many people died in just those two wars as there were living in Europe at the height of its population during the Middle Ages!
ETA: Oh, and further to add, the root causes of 9/11 were political in nature, not Religious. Al Quada didn't attack the US because of Islam, or because the US is a "Christain" country anymore than they attacked the US "Because they hate our freedoms." They attacked the US because of the US foreign policy in Middle Eastern countries such as Saudia Arabia, Isreal, and Eygpt.