That just simply isn't true. It's not been true for the past and it's not true now.
You're going to now talk about the mixed of data on transmission. But the date is quite clear that Even before boosters and even with the Delta variant while peak viral loads end up similar, you quickly reduce transmission levels and number of infections compared to unvaccinated individuals. That is if you're unvaccinated you get infected More likely, in comparison to infections non-vaccinated classroom will have significantly more sources of infection, and those that are infected in said classroom will transmit the virus for a longer period of time.
Vaccines reduce individual risk.
They more importantly for your conversation here they reduce the risk to a population.