Sanctions compliance is unfortunately fairly complex.
Let's Encrypt can issue certificates for non-government entities in Iran and Russia due to statutory exemptions protecting personal communications, alongside specific Office of Foreign Assets Control (OFAC) authorizations designed to promote Internet freedom and human rights.
We will look into whether we can make things more easily understandable in the subscriber agreement.
> You are not a person or entity that is: (a) located in, organized under the laws of, or ordinarily resident in any country or territory that is the target of comprehensive U.S. sanctions
Seems to be pretty clear that it would include non-government entities in sanctioned countries.