Because an egregious violation of someone's privacy that's can be traumatizing as a sexual assault is a minor thing.
Revenge porn is a sexual assault? Seriously? Do you also regard the iCloud compromise as a sexual assault?
His premise that revenge porn "can be as traumatizing as a sexual assault" is not in any way the same as saying "Revenge porn is a sexual assault.". What you did there was to twist his words to create a straw man to attack, saying his statement about traumatization was instead claiming actual assault. Re-read his statement and you'll see he never said what you claimed as his premise.