1) we aren’t gedolim or rabbis of communities that have reshus to give tochachah to entire communities, and certainly not to do it publicly.
2) the people we are referring to aren’t on this site, so the tochahcha is not addressing the intended recipients
3) and I think we can discuss the halachic issues of such a dinner, but the impression I’m getting (and I hope I misunderstood) is very disparaging at those who did partake in this meal.
I mean, with your logic, any public loshon hara can be rationalized.