The Crusades are a good point but they certainly didn't kill millions. Persecutions in Rome? Not a good point to bring up if one wants to indict Christianity. Tensions b/w the Holy Roman Empire (not holy, not roman, j/k!) and the Ottomans? Still hard to reach a million deaths.
Look, I'm not defending anything here. I'm just trying to point out that the scale of slaughter in the 20th century (when godless ideologies ruled the day) dwarfs previous eras. (It should be noted that much of this is due to the fact that populations are larger in the modern era...I have no clue what the percentages are of deaths in the ancient world; it could very well be that more ppl died b/c of religion as a percentage of world pop back in the day but w/o data, it's hard to make that case - but I am totally willing to hear someone out on this.)

