Everyone in history were dicks or benevolent to varying degrees. I believe this behaviour was (and is) modified by different ideologies. This should be obvious--if you don't agree, you are basically arguing that people's beliefs have no impact on their actions.
What I'm saying is that
There is really no idealogy that can be simplified as much as you're doing to Islam.
Christianity as a whole *should* be incredibly pacifist in some views of the faith. A lot of Christians are, A lot of them aren't. You can cherry pick examples to go any way you wish both in the present and especially throughout history. It would be a whole lot better to treat every example of Christian politics on its own merits rather than trying to lump it all together wouldn't it? Otherwise you're making a judgement on who the 'true Christians' are, the Crusaders or the pacifists of the early church. It's a hopeless and pointless subjective task which bears no fruit.
Or take a look at how differently Tibetan Buddhists act as compared to Sri-Lankan Buddhists, or hell, as you alluded to, how Buddhism was used to justify Japanese aggression and suicide bombing in the second world war. Do you really need to ask the real Buddhism to please stand up? Just treat the current Sinhalese version that allows oppression of Tamils separately from the current Tibetan version that discourages any sort of violent resistance to Chinese colonialism from the Second World War Zen version that acted as handmaiden to the territorial lusts of Imperial Japan. The contexts in which all of these operate is incredibly different and should be treated as such.
I really have no idea why you're resisting a request for precision here. The Islam of the Al-Qaeda/ISIS types is obviously not the Islam of Iran or (most tellingly) the Islam of the orthodox Sunni schools. Why not deal with them as we should, as not the same, rather than lumping it all under the almost uselessly generic label of 'Islam'.
Ok. If you want to say that Islam (or whatever sub-category of Islam you want to talk about)
I think here is where we start talking about different things. I'm very much asking for sub-categories of Islam. Once people start talking about 'Islam' in the general it really stops making any rational sense to me. Even a little bit of willingness to acknowledge the diversity of a faith that has 1.5 billion adherents and a history of 1.5 millenia goes a long way. You're certainly willing to deal with it to some degree at least. Harris/Hitches/Dawkins don't seem to give a damn.
If you want to speak about the kind of Islam that Al-Qaeda a-likes believe in and how it differs, or not, from the faith of other muslims then I'm more than willing to delve into it. When you start insisting on finding some sort of Unified Theory that lumps ISIS in with the general religious intolerance of the middle and late era Golden Horde then that just is way too much of a stretch for me to consider. I don't see any reason not to treat them separately across the centuries, traditions, languages, cultures, and geography that separate them rather than try to find some underlying Islamic 'thing' that Explains It All.
I'm not saying to never talk about Islam at all. I'm saying that for the extreme scope and range that you're bringing up you need to start speaking about specific versions of the faith and not just Islam in the generic.
I'm not saying that we should attribute everything to human nature. I'm saying that human nature should always be considered in all these discussions as that is the true common factor in all of this. Not Islam.
Did Stalinism's influence in the Soviet Union have as bad an influence as Buddhism's influence in WW2 Japan?
Stalinism being a modified, perhaps corrupted, offshoot of Marxism of course. And Japanese World War II era Buddhims being very different from the current Tibetan Dalai Llama version. Again there is very little value in going straight to the generic basic level rather than dealing with each different version separately.
That said, the more history I read, the worse an impression I have of Islam's influence, and the less unreasonable Harris' view that Islam (or again, some types of Islam)
In almost every one of these threads it's just that simple little qualifier that's missing. 'Some types of'. It makes a ridiculous amount of difference.
Edit: And of course you're talking about 'fundamentalist Islam' while I'm not because I honestly don't even know what it means any more. I'm glad that you use the term though (though inconsistently). Harris/Hitchens/Dawkins don't even bother to make that much of a distinction.