I said "thus" because I had just quoted this from Tom's article:
"Studies and investigations of outbreaks all point to the majority of transmissions occurring as a result of infected people spewing out large droplets and small particles called aerosols when they cough, talk or breathe. These can be directly inhaled by people close by."
Those droplets are inhaled by people who have had both shots and, in turn, spew them at unvaccinated people.