“It’s”? Are you talking about covid? Because we’re talking about other diseases, and if you’re claiming that a population fully vaccinated against mumps, other than the immunocompromised, doesn’t protect the immunocompromised from mumps, feel free to look up and compare current and past rates for mumps infections.

Then, use your half a brain to extend that to COVID. The COVID vaccines do little to prevent transmission in that if you are vaccinated, and are exposed to the virus, you will still likely become infected. But the vaccines reduce the duration of infection and reduce the viral load shed by the infected person, this reducing the probability that an infected person will spread to anyone else. If an infected person is infecting fewer people, that is a reduction in overall transmission. So when you say “’we’ve known the vaccines do not prevent transmission”, you’re completely wrong, or at the very least, equivocating, by conflating individual transmission with overall transmission rates. Here’s a link, since I doubt you’ll know what that means either: https://www.thefreedictionary.com/equivocating.