I think a lot of religions have violent aspects to them. But it's not so much to do with what you can find that is violent about the religion, it's all about the interpretation and behavior of it's believers to measure the violence of a religion. And I don't happen to think that Muslims are inherently more violent than any other Abrahamic believers; Christians and Jews would probably act the same way in the same circumstances. I mean, look at the Torah or the Bible and tell me how they are less violent than the Quran.
"All authority in heaven and on earth has been given to me. Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.” (Matthew 28:18-20)
The question asks is the Ideology of Islam dangerous, not the practitioners. If you read the Qu'ran, it calls for a lot of death. It's the same with Christianity, the ideology is horrid, but the practitioners aren't killing the gays, wiccans, and "infidels".