Depends on what you mean by "covid" here. If you're referring to the virus, then no - this is a misconception. The vaccines at best only reduce symptoms, they don't stop infection or transmission.
> versus several asymptomatic days while unknowingly contagious
This was also an early guess that turned out to be wrong. We've known this wasn't a thing for years, at least before these vaccines.
> My reply was intentionally simple in order to drive home a point about selfish versus societal viewpoints.
Right now, getting vaccinated is the selfish action because it's likely to turn you into an asymptomatic spreader. At least when unvaccinated you'll know to stay home.
This is a) insane and b) directly contradicts the point you tried to make above it.
If I remember the timeline right it was mid/late 2020 we realized that assumption was wrong, then about a year later it was apparent the vaccines weren't stopping the spread. So yeah, my statements are entirely consistent: There wasn't before the vaccines, there was after.
If vaccination causes you to experience an early immune response, versus several asymptomatic days while unknowingly contagious, then it has prevented you from spreading covid to some of those you would have otherwise.
If vaccination results in a less severe infection with lower viral load, then it has prevented you from spreading covid to some of those you would have otherwise.
My reply was intentionally simple in order to drive home a point about selfish versus societal viewpoints.