YABVU - not, particularly, for wanting CCTV on public streets, but for not understanding what it could lead to.
How happy would you be for facial recognition to become the norm, commercially as well as for policing? For you, or your family or friends to be profiled, not occasionally, but constantly, based on software potentially built with a racial bias, or location bias, or gender bias, etc? And for that information to be used to make decisions about you without a 'right of reply'?
As a PP mentioned up-thread - visible police, who work well within the communities they serve, are far more effective for prevention. Passive surveillance of the type you espouse doesn't prevent crime, just helps in some cases to apply punishment.
Maybe have a read of some of the articles in the Economist to see where the 'but I've nothing to hide...' mentality can lead (particularly the v.disturbing article about treatment of the Uighurs).