What makes a “modern society”? Is it modern because of a certain code it uses, or because it has certain qualities which make it more vital than “non modern society”? I understand that one should follow and understand technological change, but being wary toward obvious intrusion of personal space is far from being socially unacceptable.

"Modern" can just mean "current".

Or at least don't do anything that would be considered 'suspicious' within that modern society. Of course, it is hard to know what will be considered suspicious....

Whatever's convenient to dispose of people in the way of the status quo. Remember that the feds really started rounding up pot smokers on a large scale for the first time as a way to legally get rid of Vietnam war protestors. It'll happen again, and next time they'll have an infinite pit of dirt to dig through.

Nobody is 100% law-abiding or morally clean. Nobody. We're definitely all vulnerable to prosecution and blackmail. People who think they have nothing to hide aren't using their imagination properly.

This reminds me a saying like:

anything existed before my birth is old and outdated. Ideas and inventions I grew up with really changed and is changing the world. Others are useless and invade my privacy.

I cannot remember either the exact sentences or where I get this from.

It sounds like a quotation from Douglas Adams: "Anything that is in the world when you’re born is normal and ordinary and is just a natural part of the way the world works. Anything that’s invented between when you’re fifteen and thirty-five is new and exciting and revolutionary and you can probably get a career in it. Anything invented after you’re thirty-five is against the natural order of things."