The vaccines do not prevent infection but reduce the ultimate harm of the infection.
You have to pretty much be willfully ignoring this fact to not understand it at this point.
To note: I'm personally vaccinated, but people who think it is OK to restrict personal freedoms of other people based on very fluid and agenda-driven narrative about the current state of the 'scientific consensus' do not get much respect from me. Maybe it is because I'm from a country where personal freedoms are routinely abused and I value them much more than people who take these freedoms for grated.