If their point is that they get mad because people would downvote "Your Show HN isn't really that impressive", then I guess so. I would certainly downvote that kind of comment, because it's pretty much by definition a jerky comment.
But I have seen tons of reactions to Show HNs that are "How is your product different from XYZ?" or "How will you address problem Foo?" Those comments actually bring something helpful to the discussion. I've also seen, in cases where the Show HN isn't something the community generally appreciates, get fair comments along the lines of "Your product just appears to make it easier to spam people. Why should we like this?"
Offering critical commentary without a point isn't something that adds to the value of the site.
But I have seen tons of reactions to Show HNs that are "How is your product different from XYZ?" or "How will you address problem Foo?" Those comments actually bring something helpful to the discussion. I've also seen, in cases where the Show HN isn't something the community generally appreciates, get fair comments along the lines of "Your product just appears to make it easier to spam people. Why should we like this?"
Offering critical commentary without a point isn't something that adds to the value of the site.