I really would appreciate a source or link to specific metrics. When I look, I see stats about how more vaccinated individuals are getting sick in aggregate than unvaccinated, people with boosters more likely to catch over time when compared to right after a booster, and even people with boosters are more likely to get Covid than they were after getting the booster relative to unvaccinated and unboosted people. That last one could throw people for a loop if they don't realize that it is just a smaller gap representing waning efficacy of the vaccines over time again.

None of those line up with what you said very authoritatively. I'd hope you were careful than you about making such a strong claim without caveats if you used raw data. If you didn't do the legwork to account for demographics and confounding variables then you run the risk of effectively being misinformation.

Flatly stating that you're more likely to get Covid when boosted is a huge claim without getting into your implication that the effect is pernicious enough to cast doubt on increased durability of antibody response.

Not saying he's correct but you misunderstood. He's claiming they will be taking a hard right turn and you're responding to if they have taken a hard right turn. You'll want to ask him the specifics on why he believes that if you want to provide a good counterweight.