'I have nothing to hide' - how often have you heard it in a discourse about privacy? It is the one particularly troubling and discloses a lack of care or understanding of the subject.
Saying that you have nothing to hide is basically admitting that you did not yet and not plan to have any original idea or important mission to accomplish. It is like stating that you plan to watch cat videos until the rest of your life. Which hopefully is not the case.
We all might have things to hide - not only for legal reasons. If you have a new business idea or strategy, you don't want google to parse your e-mails where you discuss them. If you are running for president, you don't want details of your campaign to leak out or be seen by your competitors. If you are discussing a job opening with a potential new employer, you certainly don't want your current one to know. You can enumerate examples like this without an end.
And those are the ones that don't involve any morally questionable issues. What if you are having an affair? Hiding your bitcoin income from the tax office? Can you say with certainty that this will not happen to you?
Another issue is that you might not have anything to hide under an assumption that you live in a democratic country that respects its citizens freedom. Even if this is the case now, can you be sure that it won't change in the future? Under a dictatorship things that used to belong to human rights are suddenly something you cannot disclose - your religion, nationality or sexual orientation might be subject to oppression. Having a totalitarian government looking over your shoulder and knowing your location at all times is not only uncomfortable but also dangerous.
And even if you yourself don't have anything to hide, there are people that do. And some of them are endangering their lives to fight for your freedom. We are living in the times where our communication is transferred and stored by big private companies, who have their interest in mind. Isn't it troubling to think that your own data can be used against you to manipulate or put you in prison?
It is difficult to protect privacy and some of the scenarios seem abstract. But we all need to care as no one will do it for us.
We cannot all become activists from one day to another, but we should, for our own benefit, know when why and by whom our data is being stored and processed. And if you have an opportunity of using an encrypted messenger that does not track you, why wouldn't you? If you have a free e-mail provider that is following the same principles, why don't you use it? If there are browser plugins available for free, that block trackers, why not installing it?
Your data belongs to you and you shouldn't have to think if you have things to hide when you communicate. You should be able to decide what you make public, not the other way around!