But they are private
Are you on cloud 9. If you express an opinion, which you are entitled to do so, that doesn't suit somebody in your government i.e. you may express a supportive remark about Iran. Next thing you will have is your authorities banging on your door claiming you are a terrorist. Question, where was the unlawful enterprise you ventured on in this case? There isn't one; it is just you expressing an opinion via email to a friend. If your government want to play "Big Brother" in their 50 States, up to them and the US voters. Keep out of other nationalities email accounts you do not control the world.