This person's case is risible. My Ancestors were Greek and Irish. Neither Ireland nor Greece were evangelized by military means. People just heard what sounded to them, at the time, as a Sweet Deal (the "gospel," loosely translated, would mean something like "Sweet Deal"). That's the ideal way to do it, I would say. Whatever I think of the specific doctrines and propositions today, a religion's spread should be based on ideas that win people over. Any given faith just another article in the marketplace of ideas, and see who buys.
Now it's as detestable as it is true that after Rome made Christ Caesar, after the Church became entrenched as a sort of confederating world power, some bright bird (a cardinal, perhaps) trumped up a justification that it was mortally necessary to conquer 'em heathens in order that their souls might have a chance at salvation: come in fast, hard and give no quarter - ends justifying means, greater good and all - "There are people dying!" to quote Michael Jackson. To save even a remnant from hell, of course the virtuous thing must be to storm in blood and thunder, obliterate all opposition and grind everyone under the boot-heel 'til they see how sweet Jesus is.
Contemptible stuff, and just as contemptible are the later spates of Inquisitions and heresy hunts, zero tolerance for nonstandard views - no good news involved in the conversation, just obey or suffer. These tactics are nothing whatsoever to do with Christianity, the religion. They were the military policy, domestic and imperial, of Western Christendom - an entirely more warlike entity. Powerful, wealthy, worldly kings and princes striving for dominion have historically had an easy time finding clergy willing to bless their endeavors and cloak them in some trumped-up - but outrageously anti-Christian - justification.
An entity less warlike than Christianity would be hard to describe. As Christ spread its seeds in Galilee and Judea, as Paul spread it flowering through the Greek world, as Patrick strewed it all through Ireland, Christianity's official and only approved vector of distribution has been and is: by the word, not by the sword. By the marketplace of ideas - and never is anyone obligated to buy. Sweet deal.