I think addressing PhilGoetz's example about slavery as unsuitable doesn't invalidate his main point at all as it is only intended to provide an example. It may not be a good example but I think we can imagine good ones instead.

The central point is whether lying (at the very least intentional selection on information provided) to groups of people is required to achieve some common goods. And this is not even posited as true but asked as question (and I see no answer to that only comparably minor nitpicking).