Several people in my mentions confused about the legal and technical differences between content and metadata in communications systems.
This 2016 paper by my colleagues (@SteveBellovin, Susan Landau, Stephanie Pell, and me) probably won't make you any less confused, but will at least make you feel better about it.
https://jolt.law.harvard.edu/assets/articlePDFs/v30/30HarvJLTech1.pdf