The history of the world has seen many outbreaks of religious based violence, and certainly Christianity has more than it's share of murder and pillage.
BUT, around the world TODAY, the religion that is the home of the majority of terrorism, murder, and mayhem, is Islam.
And when liberals go out of their way to look past that fact, especially when their defense is always to point to past events such as the Crusades, they lose credibility.
The Lord's Resistance Army is still in operation today. But also, as I said, relying on religion as your fundamental explanatory variable for conflict often affords one a very poor understanding of the root causes of modern conflict. Mathematically Islam isn't a significant contributing factor, religion in general isn't in fact, and has been studied intensely by economists such as Paul Collier. Identity plurality within a contained population set (usually based around state lines), does show some statistical significance in explaining conflict and such identities can exist surrounding religious identity, but it is just as potent of a factors as say ethnic plurality, or rigid party identity, nor does it matter what religions make up said pluralistic identity.
I don't totally disagree with you, but in the case of Islam, in certain regions of the world this religion keeps much of the followers in a perpetual state of alienation from the modern world due to the refusal of a sizable number of the followers to let go of ancient fundamental beliefs and views.
Thus the growth of poverty and the growth of extremism and thus a more likely possibility that followers of this particular religion will turn to jihad to force their ways on others
Islam has surrounded a significant part of political and identity based violence recently, but that is more happenstance / situational than anything to do with theology. It has more to do with state evolution and the emergence of transnational identities in the face of weak domestic identities/ institutions than anything else. Many parts of the world face such issues, Europe did too when it was in that period of state building and identity, we even had two world wars (among many others) over it. With former colonial regions though we tend to see the rise, during the Cold War and their respective periods of independence, of socialist big men states. This was not unexpected. Capitalism was associated with the west who had just gotten done lording over these regions as autocratic governments that had prevented their freedom. So when many of these states developed afterward they swung in the opposite direction in Africa we saw the rise of African socialism, and in the Middle East we saw heavy secular nationalist regimes, socialist regimes, and even the emergence of some fascism.
As we know though socialism doesn't tend to wok out too well, throw on top the discord of just starting out and many of these states either collapsed or faced huge internal problems that required either regime change, or the hardining of political lines, dictatorial rule and a crackdown on civil society. We saw this all over the third world. Such state crackdowns wasn't very good for the fostering of broad political identities. Instead, opposition movements had to exist within society wherever they could survive. For many African states opposition then resorted to tribal lines and region specific areas of African states where they had bastions of resistance within a physical space. This led to a lot of civil conflict in Sub-Saharan Africa, and to the eventually the African spring of 1990. In the Middle East, which tended to have stronger centralized state structures and institutions, and where the reach of the government tended to be wider, the primary safe(ish) sector of opposition was within religious institutions. It was one of the only areas where public discourse could take place that the government had a harder time controlling. So we saw the emergence particularly in the 50s 60s and 70s of opposition groups surrounding religious dialogue during the period of late state failure. That's just where we are in the state evolutionary process. It isn't anything particularly special or unique, just the particulars have differed. Nor is it anything permanent. Islamists are likely to be poor rulers and like their dictatorial strong men and socialist governments before them, they will eventually be washed away in the state building process.