If you will not fight for right when you can easily win without bloodshed; if you will not fight when your victory will be sure and not too costly; you may come to the moment when you will have to fight with all odds against you and only a precarious chance of survival. There may be even a worse fate, you may have to fight when there is no hope of victory, because it is better to perish than to live as slaves.
Free societies are hopeful societies. And free societies will be allies against these hateful few who have no conscience, who kill at the whim of a hat.
As a rule, dictatorships guarantee safe streets and terror of the doorbell. In democracy the streets may be unsafe after dark, but the most likely visitor in the early hours will be the milkman.
A central lesson of science is that to understand complex issues (or even simple ones), we must try to free our minds of dogma and to guarantee the freedom to publish, to contradict, and to experiment. Arguments from authority are unacceptable.