Well I mean in many countries, blocking the surveillance agency from listening in on your calls/texts/chats is illegal. So making an app that interferes with the agencies ability to "listen in" is infact a criminal enterprise.
How about adding "illegal thoughts" to that mix too. It is only one short step away from wearing a monitoring "headband". All subversion grows its first root in the mind of the citizen. Nipping this in the bud through detection and re-education guarantees peace and safety of society and the nation. If you have done nothing wrong, you have nothing to hide.
Don't have to like it but the law is the law.