Why does religion start so many war's? 
It doesn't. That's a bit of a myth.
Most humans feel the need to "belong" to groups of like-minded individuals. It's a pack instinct. So, they join clubs, either tangible or intangible, either formally or by default. What power-hungry individuals and groups then do is to hijack the groups. You can unite people by hatred and fear far easier than by love and confidence, so they create the right conditions to whip up ever stronger ties between the individuals and their groupings. On a local level, this can be through one group of football fans being whipped up to hate fans from another club. It's bizarre, but it happens. Of course, on a national or international level, the exploitation of mass identities is a very efficient way of uniting populations by those who seek to gain political power. As in WWII, Hitler used a hatred of Jews to unite his people. We have seen the same tactics used by Castro in Cuba, by Milosovic in the former Yugoslavia and, more recently, by Chavez in Venezuela. In some cases, but certainly not all, national identity may be tied into religion.
The Islamic fundamentalism which the lady in the video rightly criticises has little to do with personal faith, but a lot to do with distortion of texts with the sole aim of whipping up hatred of the West. I should imagine the vast majority of Muslims do not support the fundamentalist views but the extremist network has become so entrenched in everyday society that individuals are afraid to speak out less they get ejected from the "club".
Could anyone imagine a football fan standing up amongst his peers on the terraces and saying "Stop this hateful chanting against the other team, we're here for the footie". Er, no, they wouldn't. Yet the paradox is that many of them would support that view, even though they may be seen publicly join in the chanting.
So, no, it's not religion per se, it's the manipulation of human frailties by those who crave power.