If postal mail passes through an IRS person's hands for some legal reason, I believe they are legally entitled to read all the postcards in your mail, as there is no expectation of privacy on them, given that they're postcards.
Email is the same way: the contents are naked, written on the side of the packets for anyone on a given network segment to view if the traffic comes their way.
Just as we put mail in envelopes, we should encrypt our email if it's not for anyone and everyone to read if they happen to be standing "near" it when it goes by.
And how do you tell if the hacker is "part of", or working for / at the behest of, an enemy state? The enemy state may find it beneficial to make it as difficult as possible to determine that someone is working for them, since it seems like it would benefit both the state and the hacker to do that.
It was intended as a joke, not an insult, but you've just said that it's true, which either means it is an insult, regardless of how it was intended, or you're now creating an insult which coincidentally reads exactly the same as the original "joke". That's like people who say racist things but they only say them ironically, or they only intend them as a joke - not an insult.