Answer by Jim Ashby:
If, by "Islam", you mean the ideology informed by the Quran and ahadith, then the answer is an unequivocal Yes. But I would add that ALL monotheistic religions have demonstrated violence and intolerance: particularly when united with powers of state. And Islam is the most monotheistic one of all.
In another answer, elsewhere on Quora, I've recently copy-and-pasted a very long list of ayat (verses) from the Quran that make it clear you must fight for Allah and Jihad. Rather than post it again, you can find many violent ayat by using Google search. Many hits will, of course, be from anti-Islamic sites but the ayat they quote will actually come from the Quran and should be accompanied by proper citations. There are also many from ahadith.
According to Islam there are 2 main divisions of the world: Dar al-Islam (House of Islam) and Dar al-Harb (House of War). The House of Islam is, of course, Muslims. The House of War is infidels (non-Muslims). There must always be war until there's no infidels. It doesn't get any more us-versus-them than THAT!
The ayat in the Quran that infidels usually refer to as "jihad verses" contain the phrase "Qitāl fī sabīl allāh" (fighting for the sake of Allah).
Disrespecting Allah, Islam, the Quran or Muhammad is cause for jihad. Islam is NOT peaceful and tolerant if you don't behave like a Muslim . . . even if you're an infidel with no knowledge of Islam. If you value democracy, you're a heretic.
So the next time murderous Muslim rioting is in the news because of some cartoon mocking Muhammad or some nut-case burning Qurans or some naive teacher naming her teddy bear "Muhammad", remember that Muslims are SUPPOSED to fight for the sake of Allah. If they respond so violently to such minor events, how do you think they feel about Jews (who have, historically, been subjugated dhimmi) occupying holy Muslim land?
Everybody should read the Quran. Learn from the book that informs the religion. You'll better understand how Islam manifests in our world.