Security measures or privacy invasion?

Welcome to the 21st century. Here we have lot's of great things, including the internet. And do you know what people tend to do with great things? Ruin them for the others.
Internet is supposed to be a free place, witch belongs to no one and where every one can share their thoughts, opinions and creations, within a certain limit, because things like child pornography and drug-selling websites are not seen on normal web - on surface web. Overall, it is a democratic place to share your thoughts and store your information.
But instead of being this free place where people can do whatever they want, and share it with whoever they select, governments around the world are changing the game - by breaking the rules.
National Security Agencies from various countries have taken the internet as an opportunity for monitoring and spying on their own citizens, all under the excuse of the "war on terror".  But how do they do it?
Considering that some countries don't have the funds or infrastructure to hack into their citizens network, whole nations actually hire the service, buying it off-shelf. But who would provide such information about thousands of civilians from a foreign country? Well, there sure are a lot of people who do it because it is a 5 billion dollar industry.

https://www.youtube.com/watch?v=R63CRBNLE2o

And why should we - innocent civilians who have nothing to hide - fear that the government is obtaining information which we assumed was private?
Being monitored and being aware of it changes our human behavior. There have been many studies about it. Also, we don't know what the government is doing with the information they are getting. 
There is no limit to the access they have. Even encrypted information is just a few clicks away from the nations authorities.

Heloísa Marshall, Lucas Toniolo & Matheus Rabelo, 3C