The only coaching going on with Launch HNs is from me and tomhow, and I can tell you that we're constantly urging people to tone down grand claims, provide concrete examples, accessible demos, and so on—partly because it makes the posts more interesting, and partly to reduce surface area for the snarky and rigid objections that internet forums optimize for.

We don't do a perfect job of this, because (1) Launch HN coaching is on top of our main jobs running HN and we only have so many hours; and (2) startup founders' priority is working on their startup (as it should be!). They only have so many cycles for reworking everything to suit HN's preferences, which are idiosyncratic and at times curmudgeonly or cynical. Curmudgeons and cynics can't be convinced in the first place so it's not a good idea for a founder to put too much time into indulging them.

Some of what you're saying here boils down to that their home page shouldn't have any marketing tropes at all (e.g. testimonials, companies-using-us, etc.). I don't like those tropes either, but this is an example of what I mean by an idiosyncratic preference. Companies do that kind of thing because, obviously, it works. That's how the world is. The only thing that you accomplish by angrily blaming a startup founder for doing standard marketing is to make the discussion dyspeptic and offtopic. And yes, I do use the word "dyspeptic" too much :)