Re: September 11, 2001, the day when Americans decided that freedom was not worth the risk.
If you want to trust big brother, that's your right. Me? I trust that two or three generations of exposure to a society that believes in intrinsic liberty of the individual will remove from anyone the desire to live under Sharia - or any other theocratic, totalitarian law.
There are plenty of Muslims living in Alberta; they've been here for quite some time. I have never met a single one that thought Sharia was a good plan. I have met thousands who would fight against Sharia and be perfectly willing to die defending the freedoms we all hold dear.
I don't fear Muslisms the way you seem to. Certainly I don't fear the ones in my nation. They aren't "Muslims". They are Canadians. That they believe in a religion is of no concern to me so long as they aren't dedicated to forcing others to believe...and the ones I've met here have no interest in doing so.
As you your Nazi question...
...yes. You do allow the Nazis the right to run for office, become elected and form a government. You do not track them with Big Brother and murder them before they can do something bad. You presume people are innocent UNLESS they are proven to be guilty of something. It is the price we pay for liberty: eternal vigilance.
For us to be truly free we must acknowledge the intrinsic rights to liberty and freedom of all others, including those who disagree with us. We can only act if others choose to violate the laws of our society. NOT BEFORE.
You also present a false dichotomy: that the only alternatives are Big Brother and Genocide. That is utterly fallacious. The reality is that in a properly vigilant society there is a place in between where you catch those in charge violating laws, freedoms and fundamental liberties after they have done some damage but before they have committed crimes anywhere near that scale.
Right now, today, that is what all the people in this thread are up in arms about. There are people in charge of the USA who have committed crimes, violated freedoms and ignored fundamental liberties. We are outraged and demanding action be taken before those corrupt individuals start committing genocide.
Given some of the paranoid delusions I've seen here, it may well not be far off until some dumb shit decides that "the terrifying Muslims" need a "final solution" and we'll be right back at war again; this time against those who used to be our own leaders. That you cannot see this...that scares me.
You pull up Nazis as an example of why we must violate the liberties of all to catch the very, very few without understanding the irony of your example. It is exactly that sort of thinking that allowed the Nazis to evolve as they did. They certainly didn't start out to destroy the Jews/Gypsies/etc. They set out to reshape a battered Germany into an economic superpower. The rest snowballed as the dude in charge went nuts and those around him either followed, were more nuts than him, or wiped out those that weren't nuts.
You don't seem to understand that evil movements, organizations and governments don't start out with a subterranean lair and a bald guy petting a cat. They start out with a group of people doing what they think is right. They compromise one ideal then another and then another. Their morals and ethics fall like dominoes as they fixate on the end, justifying any means to achieve it.
"The right thing" turns into something monstrous and those who have become obsessed with the often originally noble end become blind to the horrors they have wrought. Some wise up, but generally by the time they do they have surrounded themselves with fanatics. Fanaticism reinforces fanaticism and it gets pretty ugly from there.
Mass surveillance of innocent people is not right. There is no moral or ethical justification for that activity. It is a means that is unacceptable towards any end.