and believe it or not, it is the left, not the right, that is known for its history of terrorism and violence...
Is that the case? While Stalin was hardly a humanitarian, to say the least, I don't recall the Italian fascists as the humanists you portray them... While the term Nazi was supposed to include the term socialist, the Nazi party was hardly a pro-gay-rights, pro-choice environmentalist bunch of guys, now were they? The definitions of left and right do not stay static as years go by, and the soviet regime under Stalin, while holding a rather radical left wing economic approach, was right wing (as defined in our days) in many other fields.
Of course both sides have radicals, and of course these radicals are, well, radical. You must however hand it to the left-wing radicals, DMan, that fewer of them seem inclined to burning and lynching people, at least in the modern US and Europe.