Manufacturers, CDC, etc. were explicitly clear about the difference between preventing infection and preventing severe illness upfront. If you heard, "How can you be so cruel? Take it for grandma," and went along with it thinking that that meant transmission is prevented, then you received that "message" from someone who - for lack of a better phrase here - was not an "official" messenger and/or was speaking out of ignorance, and you then opted to read no further into the accuracy of that statement yourself.
There are countless videos out there of officials touting that "the vaccinated do not transmit covid" but not that the goalposts have shifted, we're supposed to forget all about it.
Does "officials" mean the manufacturers and the bodies that approved the vaccines for use? Or does it mean politicians who spoke out of ignorance and/or opportunism?
when talking about mistrust, lying politicians are a fair target. There has been a lot of that going around this pandemic. If the argument is that the politicians lied but the CDC, WHO and other bodies did not... well I don't know what to tell you, they definitely did get caught lying. repeatedly.