[stordoff]

I suspect it's partially an emotional response to ID cards - there's no current requirement to carry (or hold) ID, and the concept conjurers up clear images of Nazi Germany.

Regarding blinds, I doubt many people even think about it - you aren't doing anything private (or even interesting most of the time), so it just doesn't occur to you. It's also generally considered rude to stare into people's houses, so even if they can, there is a general presumption that people won't. It's quite possibly related to your last paragraph - there's no culture of shielding your day-to-day life because they has never been anything really to shield it from ("no need to hide" being subtly different to "nothing to hide" - even people with things they would rather not be public don't necessarily see the need to conceal them from the government).