Despite thinking this covid stuff is all bullshit, this argument is completely flawed. If a vaccine reduces the infection rate by 50%, then it essentially wipes out the disease, because it's twice as difficult for it to hip between people. Vaccines are not binary in that they "work" or "don't work," so using that type of terminology makes us look stupid (i.e. "at risk" vs "not at risk." We should be saying something like "if it doesn't materially reduce the risk, then ...")

On the flip side, I don't think COVID warrants a vaccine, so I usually argue from that perspective. The death rate just isn't high enough for me to care.

Edit: To be clear, I will never get the jab, and I do not believe it materially improves outcomes. It's just that no one with half a brain cell will be convinced by a naive argument.