/u/shlin28's response to this in these two threads here and here is worth reposting as it's pretty much perfect.

Basically: yes, he is misrepresenting every statement he makes.

If I could just add something to the discussion though it's in relation to this statement that he makes at the very start of the video: "Whenever you're dealing with an apologist for Islam, or even a Muslim, and you bring up Jihad, almost immediately they kick back to you: what about those terrible crusades?"

I think that actually really misunderstands the argument that contemporary (or near-contemporary allowing for the 20-year-rule) jihadists/radical Islamists are making. Jihadists don't justify their actions in relation to The Crusades (1095-whatever your preferred closing date several centuries ago may be), rather their point is that Western imperialism in the Middle East over the course of the past two centuries and continuing down to the present is itself a Crusade. As a result, Jihadi rhetoric refers to living breathing westerners in the region as Crusaders. So the Muslim Brotherhood for instance would refer to UN actions in Palestine in the 40s and 50s as "a new declaration of Zionist-Crusading war against the Arab and Islamic peoples."

As Richard Mitchell writes in The Society of Muslim Brothers:

"The full identification of Zionism with crusading Western imperialism was indicated by the interchangeable use of terms such as 'European crusading'... and 'Jewish crusading'.... In so far as the Brothers saw religion not as a mere facet of society or culture but as synonymous with these, 'crusade' had both political and cultural connotations for them. 'Western imperialistic crusading' thus appeared as an attempt not only to conquer Muslim lands but to subvert Muslim society.

He then quotes Said Qutb's remarks on the subject noting:

General Allenby [who led British forces in Palestine in WWI] was no more than typical of the mind of all Europe when, entering Jerusalem during World War I, he said: "only now have the Crusades come to an end."

and:

Crusading was not confined to the clangor of arms, but was, before and above all else, an intellectual enmity.

European imperial interests can never forget that the spirit of Islam is firmly opposed to the spirit of Imperialism...

There are those who hold that it is the financial influence of the Jews of the United States and elsewhere which has governed the policy of the West. There are those who say it is English ambition and Anglo-Saxon guile which are responsible.... There are those who believe that it is antipathy between East and West.... All these opinions overlook one vital element in the question..., the Crusader spirit which runs in the blood of all Westerners.

In terms of justification for Jihad, Mitchell continues while quoting Qutb:

...Qutb warns the Brothers that 'spiritual and mental imperialism is the true danger' for unlike military or political imperialism which inspires opposition, this type dulls, calms, and deceives its victims. 'Holy war' must be declared against 'the apparatus which directs the operation of deception': the 'modern' techniques of imperialism of the 'free world'....

So I suppose it's possible that Warren's interlocutors are justifying contemporary Jihadis with reference to the Crusades "whenever" he brings up the topic-- that's not an argument I have ever come across personally. But it sure sounds to me like he's just ignorant of what "The Crusades" means in Jihadi ideological thinking.

This has continued right down to what is probably the most recent rhetorical such example I can reference within this sub's rules: Osama Bin Laden's 1996 declaration of holy war against the United States. As quoted in Princeton Readings in Islamist Thought:

The people of Islam have awakened and realize they are the main target of the aggression of the Zionist-Crusader alliance.

and:

2 . the inability of the [Saudi] regime to protect the country, and the fact that it permitted the enemy of the umma [i.e. the Islamic nation] -- the American Crusader forces -- to occupy the land for many years. The Crusader forces have become the principal reason for our disastrous situation, particularly in regard to economics, given the regime's unjustified, extensive spending to support these forces.

So yeah, in addition to the historical issues with what he's discussing, which are many, it's really hard for me to trust a guy who has founded his own "Center for the Study of Political Islam" who doesn't seem to understand the claims of political Islam.

edit: also, lol, I just noticed this: "I created a database." The database is here: http://cspipublishing.com/statistical/charts/Islam-BattlesDate.pdf

You can scroll down and see that what he did for well more than 400 of them was go on Wikipedia and some defunct website called nethelper.com and make a spreadsheet. Hell of a database you got there Bill, real top notch sources.

This video is posted regularly in this sub. It is essentially a piece of propaganda and should not be considered a proper historical overview. Here is the most extensive answer (do read the follow-up too) to the question.